Wiley-IEEE Press Sampler. Communications Technology Power and Energy

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1 Wiley-IEEE Press Sampler Communications Technology Power and Energy

2 Contents 5G STANDARD DEVELOPMENT: TECHNOLOGY AND ROADMAP By Juho Lee and Yongjun Kwak Chapter 23 of Signal Processing for 5G: Algorithms and Implementations WHY IS PM IMPORTANT, ESPECIALLY IN TELECOMMUNICATIONS By Celia Desmond Chapter 2 of The ComSoc Guide to Managing Telecommunication Projects PERSONAL PROTECTION (SECURITY) By Steven W. Blume Chapter 10 of Electric Power System Basics for the Nonelectrical Professional, Second Edition PREDICTIVE CONTROL OF A THREE-PHASE INVERTER By Jose Rodriguez and Patricio Cortes Chapter 4 of Predictive Control of Power Converters and Electrical Drives Interested in learning more about the custom digital solutions Wiley-IEEE Press can offer your business? Contact Donna Marcum at dmarcum@wiley.com or

3 23 5G Standard Development: Technology and Roadmap Juho Lee and Yongjun Kwak 23.1 Introduction Standards Roadmap from 4G to 5G Preparation of 5G Cellular Communication Standards Concluding Remarks 575 References Introduction The wireless cellular network has been one of the most successful communications technologies of the last three decades. The advent of smartphones and tablets over the past several years has resulted in an explosive growth of data traffic. With the proliferation of more smart terminals communicating with servers and each other via broadband wireless networks, numerous new applications have also emerged to take advantage of wireless connectivity. As 4G LTE-Advanced [1, 2] networks mature and become a global commercial success, the research community is now increasingly looking at future 5G technologies, both in standardization bodies such as 3GPP and in research projects such as the EU s FP7 METIS [3]. ITU-R has recently finalized their work on the vision for 5G systems, which includes support for an explosive growth of data traffic, support for a massive number of machine-type communication (MTC) devices, and support for ultra-reliable and low-latency communications [4]. While today s commercial 4G LTE-Advanced networks are mostly deployed in legacy cellular bands from 600 MHz to 3.5 GHz, recent technological advances will allow 5G to utilize any spectrum opportunities below 100 GHz, including existing cellular bands, new bands below 6 GHz, and Signal Processing for 5G: Algorithms and Implementations, First Edition. Edited by Fa-Long Luo and Charlie Zhang John Wiley & Sons, Ltd. Published 2016 by John Wiley & Sons, Ltd.

4 562 Signal Processing for 5G new bands above 6 GHz including the so-called mmwave bands. There are coordinated efforts across the world to identify these new spectrum opportunities, with decisions expected for new frequency bands below 6 GHz at the World Radio-communication Conference (WRC)-2015, and for new frequency bands above 6 GHz at WRC-2019, respectively. From the 5G technology roadmap perspective, we expect a dual-track approach to take place over the next few years in 3GPP. The first track is commonly known as the evolution track, where we expect that the evolution of LTE-Advanced will continue in Rel-13/14 and beyond in a backward-compatible manner with the goal of improving system performance in the bands below 6 GHz. It is also our expectation that at least a part of the 5G requirements could be met by the continued evolution of LTE-Advanced. For example, latency reduction with grant-less uplink access and shortened transmission time interval (TTI) could reduce over-the-air latency to less than 1 ms. The second track is commonly known as new radio access technology (RAT) track, which is not limited by backward-compatibility requirements and can integrate breakthrough technologies to achieve the best possible performance. The new RAT system should meet all 5G requirements as it would eventually need to replace the previous generation systems in the future. The new RAT track is also expected to have a scalable design that can seamlessly support communications in both above and below 6 GHz bands. The rest of this chapter is organized into the following three sections, focusing on the technologies for the air interface of radio access networks. Section 23.2 is devoted to the standards roadmap from 4G to 5G. In Section 23.3, we will provide an overview of major enabling technologies and a more detailed roadmap of the 5G standard development and its deployment. Section 23.4 is the final section, which presents the summary of this chapter Standards Roadmap from 4G to 5G Since the publication of the Rel-99 standards supporting wideband code division multiple access (WCDMA) a representative 3G technology 3GPP has been playing an important role in evolving cellular communication standards to 4G, namely LTE and LTE-Advanced. 3GPP is a partnership project between regional standardization bodies, or organizational partners (OPs). 3GPP was established in 1998 and has seven OPs as of 2015: ARIB and TTC from Japan, ATIS from USA, CCSA from China, ETSI from Europe, TSDSI from India, and TTA from Korea. After the success of 3G technologies, 3GPP introduced LTE as Rel-8 in 2009, and LTE-Advanced as Rel-10 in 2011, the latter declared by ITU-R IMT-Advanced technology and often called 4G. There has been continuing further evolution toward 5G. The 3GPP organization and its overall roadmap from LTE in Rel-8 to LTE-Advanced in Rel-13 are shown in Figures 23.1 and 23.2, respectively. The project coordination group coordinates the projects performed in 3GPP. Each technical specification group (TSG) decides whether specifications for a technology will be developed, typically taking into account the outcome of the related feasibility study in its working groups (WGs). WGs develop technical specifications, which are then formally approved by their TSG. LTE in Rel-8 was the first standard in 3GPP that utilized frequency division multiplexing: orthogonal frequency division multiplexing (OFDM) in the downlink and single carrier frequency division multiple access (SC-FDMA) in the uplink as illustrated in Figure SC-FDMA is a variant of OFDM, where discrete Fourier transform (DFT) processing is applied to the input signal before inverse DFT (IDFT) so that the output of IDFT mimics a single carrier signal. The peak-to-average power ratio of SC-FDMA is smaller than that of

5 5G Standard Development: Technology and Roadmap 563 Project Coordination Group (PCG) TSG RAN Radio Access Network RAN WG1 Radio Layer 1 TSG SA Service & System Aspects SA WG1 Services TSG CT Core Network & Terminals CT WG1 MM/CC/SM (lu) RAN WG2 Radio Layer 2 & Radio Layer 3 RAN WG3 lu, lub, lur, S1, X2, and UTRAN/E-UTRAN SA WG2 Architecture SA WG3 Security CT WG3 Interworking with External Networks CT WG4 MAP/GTP/BCH/SS RAN WG4 Radio Performance & Protocol Aspects RAN WG5 Mobile Terminal Conformance Testing RAN WG6 GERAN Aspects SA WG4 Codec SA WG5 Telecom Management SA WG6 Mission-Critical Applications CT WG6 Smart Card Application Aspects Figure GPP organization LTE LTE-Advanced Rel-8 Rel-9 Rel-10 Rel-11 Rel-12 Rel-13 Mar 2009 Mar 2010 June 2011 Mar 2013 Mar 2015 Mar 2016 Figure 23.2 Overall roadmap from LTE in Rel-8 to LTE-Advanced in Rel-13 an OFDM signal and hence SC-FDMA helps increase the uplink coverage. The maximum bandwidth is 20 MHz, providing a 300 Mbps peak rate on the downlink with 4 4MIMO and a 75 Mbps peak rate on the uplink. It is worth noting that the OFDM waveform on the downlink does not require a complicated equalization at the user equipment 1 (UE) receiver and hence helps reduce UE receiver complexity. This property motivated the specification of 4 4 MIMO on downlink from the very first release of LTE. LTE Rel-9 included a few 1 3GPP terminology for a mobile device.

6 564 Signal Processing for 5G IDFT Freq. DFT S 0 S 1 S 2 S 10 S 11 (a) (b) Figure 23.3 Signal generation for (a) OFDM on downlink and (b) SC-FDMA on uplink Contiguous Intra-band Carrier Aggregation of five CCs (20 MHz CC 5) f Non-contiguous Intra-band Carrier Aggregation of 3 CCs (20 MHz CC 3) f Band x Band y f Inter-band Carrier Aggregation of 2 CCs (20 MHz CC 2) Figure 23.4 A few examples of carrier aggregation with up to five component carriers (CCs) additional features, for example emergency call, that was required to support voice calls over LTE. LTE-Advanced standard in Rel-10 was developed to meet not only IMT-Advanced requirements but also commercial requests for accommodating increased data traffic. As a natural approach for increasing the peak rate, aggregation of up to five component carriers was specified, resulting in the use of 100 MHz at maximum. A few examples of carrier aggregation are shown in Figure It should be noted that carrier aggregation has been one of the most successful features of LTE-Advanced because it enables mobile network operators to provide higher peak rates and to improve the operational efficiency of radio access networks by utilizing scattered frequency resources. In addition, MIMO was further enhanced through the introduction of 8 8 MIMO and 4 4 MIMO on the downlink and uplink, respectively. A combination of carrier aggregation and the larger order of MIMO provided 3 Gbps and 1.5 Gbps peak rates on the downlink and uplink, respectively.

7 5G Standard Development: Technology and Roadmap 565 Support of MIMO with eight transmit antennas at the enhanced Node B 2 (enb) necessitated introduction of a UE-specific demodulation reference signal (DM-RS) together with a channel status information reference signal (CSI-RS). This is because too much overhead results from increasing the number of common reference signal (CRS) ports, which are transmitted in a continuous manner (in every subframe). The DM-RS is transmitted, and introduces overhead, only for the UEs to which downlink transmissions are scheduled, and the CSI-RS overhead can be minimized by increasing its transmission period as shown in Figure 23.5, where RE, RB, and PRB denote resource element, resource block, and physical resource block, respectively. While the carrier aggregation and MIMO are mainly aimed at increasing the peak rate, support of heterogeneous networks consisting of macro and pico cells on the same frequency layer by relying on time-domain interference coordination is a remarkable step that significantly improves the spectrum-utilization efficiency. Following the improvements in peak data rates and system capacity provided by MIMO in LTE and LTE-Advanced, it was also shown to be possible to provide further performance improvement by having coordinated transmission and reception between multiple points [5], where a point can be treated as a set of geographically co-located transmit antennas, with the exception that sectors of the same site are considered different points. The Rel-11 standard introduced specification support for coordinated transmission in the downlink and coordinated reception in the uplink, which is commonly denoted coordinated multipoint (CoMP). The assumed deployment scenarios for CoMP illustrated in Figure 23.6 include homogeneous configurations, where the points are different cells, as well as heterogeneous configurations, where a set of low power points for example remote radio heads (RRHs) or pico cells are located in the geographical area served by a macro cell. For coordinated transmission in the downlink, the signals transmitted from multiple transmission points are coordinated to improve the received strength of the desired signal at the UE or to reduce the co-channel interference. The major purpose of coordinated reception in the uplink is to help ensure that the uplink signal from the UE is reliably received by the network while limiting uplink interference, taking into account the existence of multiple reception points. While Rel-12 continued the evolution towards improving the peak rate by aggregating the available frequency resource and improving spectral efficiency, it also started specification of features that were required for support of new services such as machine-type communications and device-to-device communications (D2D) that had not been a major focus of previous releases. The features of the first category include the following: Small cell enhancement: Dual connectivity was introduced to enable a UE to connect to both the macro cell layer, which provides mobility support on lower frequencies, say 700 MHz, and the small cell layer, which provides a fat data pipe on higher frequencies, say 3.5 GHz. Time division duplex (TDD)-frequency division duplex (FDD) joint operations: Joint operations of both TDD and FDD carriers is important and useful for mobile network operators owning both TDD and FDD carriers. In order to enable this, the carrier aggregation between TDD and FDD carriers was specified in Rel-12. Enhanced interference management and traffic adaptation for TDD: This feature introduced specified support of dynamic adjustment of uplink and downlink resources in TDD 2 3GPP terminology for a base station.

8 566 Signal Processing for 5G : CRS REs : CSI-RS REs : DM-RS REs PRB 0 PRB 1 PRB 2 PRB 3 PRB 4 PRB 5 Scheduled RBs Subframe 0 Subframe 1 Subframe 2 Subframe 3 Subframe 4 Subframe 5 Subframe 6 Subframe 7 Subframe 8 Subframe 9 Figure 23.5 CSI-RS subframes Downlink MIMO support in LTE-Advanced with DM-RS and CSI-RS

9 5G Standard Development: Technology and Roadmap 567 Scenario 1 Scenario 2 Macro Cells Scenario 3 CoMP Scenario 4 Macro Cell Coordination Area enb High Power RRH Pico Cell Low Power RRH Figure 23.6 CoMP scenarios considered for the specification support of CoMP in LTE Rel-11 systems. While the dynamic adaptation of uplink and downlink resources according to the traffic situation has been understood as one of the biggest benefits of TDD systems, it was not really supported by standards in traditional macro-cell-based TDD systems due to the interference between uplink and downlink that would be caused if neighbor macro cells changed uplink downlink ratios individually. The increasing need for small-cell operation justified the need for specification of this feature as it became feasible to assume the existence of isolated small cells or groups of small cells. Network-assisted interference cancellation and suppression: Specification support was introduced to reduce the search complexity for determining the transmission parameters of interference signals from neighboring cells in an advanced UE receiver; for example scrambling sequences used for the reference signals of neighboring cells. Inter-eNB CoMP: Network signaling between enbs was introduced to enable coordinated downlink transmission from a set of enbs connected with non-ideal backhaul. Note that CoMP in Rel-11 assumes an ideal backhaul between transmission points. Rel-12 standard includes air-interface specifications for cost-efficient support of MTC by introducing UE category 0, where the maximum data rate is 1 Mbps and only one receive antenna is supported at the UE. For support of D2D operations, the Rel-12 standard specified peer discovery as well as direct communication between proximity UEs. Application of D2D includes not only commercial cases such as advertisements and social network service, but also public

10 568 Signal Processing for 5G safety operations especially for the case when mobile networks have collapsed, for example due to earthquakes. In the continued evolution of LTE-Advanced in Rel-13 and Rel-14, it is important to emphasize continuity and backward compatibility in order to leverage the massive economies of scale associated with the current ecosystem that has developed around the LTE/LTE-Advanced standards from Rel-8 to Rel-12. While improving the spectral efficiency has traditionally been emphasized, the importance of supporting diverse requests from mobile network operators was also well recognized in planning the features to be standardized in Rel-13 and upwards. As the result of this consideration, Rel-13 includes the following major features: full dimension MIMO (FD-MIMO) for a drastic increase of spectral efficiency via use of a large number of antennas at the base station, licensed assisted access (LAA) for utilizing unlicensed spectrum while guaranteeing coexistence with existing devices, carrier aggregation with up to 32 component carriers, further cost reductions for MTC devices that can also support extended coverage. FD-MIMO heavily relies on advancement of signal processing technologies and is one of the key candidate technologies for the evolution from 4G to 5G cellular systems. The key idea behind FD-MIMO is to utilize a large number of antennas placed in a two-dimensional (2D) antenna-array panel for forming narrow beams in both the horizontal and vertical directions. Such beamforming allows an enb to perform simultaneous transmissions to multiple UEs, realizing high-order multi-user spatial multiplexing. Figure 23.7 depicts an enb with FD-MIMO implemented using a 2D antenna array panel, where every antenna is an active element allowing dynamic and adaptive precoding across all antennas. By utilizing such precoding, the enb can simultaneously direct transmissions in the azimuth and elevation domains for multiple UEs. The key feature of FD-MIMO in improving the system performance is its ability to realize high-order multi-user multiplexing. 3GPP has conducted several studies since December 2012 in an effort to provide specification support for FD-MIMO. The first step was a study for developing a new channel model for future evaluation of antenna technologies based on 2D antenna-array panels [6]. The channel model provides the stochastic characteristics of a three-dimensional (3D) wireless channel. Based on the new channel model, a follow-up study item on FD-MIMO was initiated in September 2014 to evaluate the performance of FD-MIMO and identify key areas in LTE specifications that need to be enhanced in order to support 2D arrays with up to 64 antenna ports [7]. In June 2015, 3GPP started a work item to specify FD-MIMO operations for LTE-Advanced in Rel-13. FD-MIMO has two important differentiating factors compared to MIMO technologies from previous LTE releases. First, the number of antenna ports at the enb transmitter is increased from 8 to 16. As a result, FD-MIMO significantly improves beamforming and spatial user multiplexing capabilities. Second, specification support for FD-MIMO is targeted for antennas placed on a 2D planar array. Using the 2D planar placement is also helpful to reduce the form factor of the antennas for practical applications. LAA aims to use unlicensed spectrum as a complement for LTE systems operating in licensed spectrum to meet the sharply increased demand for wireless broadband data [8]. For tight integration of the unlicensed spectrum as a capacity boost with the licensed spectrum, LAA uses carrier aggregation. Considering the availability of the 5-GHz unlicensed band that

11 5G Standard Development: Technology and Roadmap 569 can provide tens of 20-MHz carriers, carrier aggregation with up to 32 component carriers is specified to fully utilize the available frequency resource in both the licensed and unlicensed spectrums. Although the licensed spectrum affords operators exclusive control for providing guaranteed quality of service (QoS) and mobility, LTE operations in the unlicensed spectrum need to coexist with the operation of other radio access technologies such as WiFi. In order to meet the coexistence requirement, the listen-before-talk mechanism has been specified to govern when a wireless resource in the unlicensed spectrum can be utilized. It should be noted that the LAA specification in Rel-13 only supports downlink transmissions. Machine-type communication through cellular networks is emerging as a significant opportunity for new applications in a networked world where devices communicate with humans and with each other. The Rel-12 specifications for MTC UEs achieved cost reductions of about 50% relative to the lowest category LTE UEs (category 1 LTE UEs) and Rel-13 MTC specifications are expected to achieve an additional 50% cost reduction primarily through restrictions in transmission/reception within only six resource blocks of a system bandwidth per transmission time interval and a lower power amplifier gain, where the RB bandwidth is 180 khz [9]. The absence of receiver antenna diversity and the reduction in power amplifier gain can result in significant reductions in coverage, even for Rel-13 MTC UEs that do not experience large path-loss. A key design target is to provide up to 15 db coverage enhancement while minimizing the impact on network spectral efficiency and MTC UE power consumption. The coverage enhancement is mainly achieved by repeated transmissions of same signals. In order to reduce to the required number of repetitions, other physical-layer techniques, such as use of multiple contiguous TTIs for a transmission to improve channel estimation accuracy at the receiver and frequency hopping across repetitions to increase the frequency diversity gain, are also specified. Narrowband Internet of Things (NB-IoT) is specified in Rel-13 as another approach Patch antenna FD-MIMO 2D antenna array Feed network Connector CPRI IP LTE infrastructure FD-MIMO baseband High-order MU-MIMO Figure 23.7 Conceptual diagram of a FD-MIMO system realizing high-order MU-MIMO through a 2D antenna array

12 570 Signal Processing for 5G for efficient support of the cellular Internet of Things (IoT) with low throughput up to about 50 kbps using a very narrow bandwidth of 180 khz. The NB-IoT can be deployed by reusing a GSM carrier of 200 khz bandwidth, using a single RB in LTE systems, or using a part of the guard band in LTE systems. Discussion of the evolution of LTE-Advanced in Rel-14 has already started. FD-MIMO and LAA introduced in Rel-13 will naturally continue to be enhanced. In case of FD-MIMO, the number of enb transmit antenna ports can be increased to 32. The LAA specification is expected to add support for uplink transmissions in the unlicensed band. In addition, it is expected that Rel-14 will introduce technologies for latency reduction, which is one of the most important aspects for improving the user experience but has not been improved much since the introduction of LTE. The uplink data transmission consists of a scheduling request, a resource grant and a data packet transmission. The request-grant procedure represents a big portion of the latency required for uplink data transmission, especially for the transmission of small payloads such as acknowledgement signaling in the file transfer protocol (FTP). By introducing a grantless procedure in other words, removing the request-grant procedure it becomes possible to significantly reduce the data download latency that is caused by the slow-start procedure of the transmission control protocol (TCP). Another approach gaining attention is to shorten the TTI length. In the current LTE standard, the TTI length is 1 ms and is equal to the duration of a subframe, which consists of 2 slots and corresponds to 14 OFDM symbols with normal cyclic prefix (CP) length. The TTI length will be reduced to for example 1 slot (0.5 ms) while guaranteeing backwards compatibility; in other words it will be possible for legacy UEs supporting the current TTI length of 1 ms to coexist with the new UEs supporting the reduced TTI length. Technologies for vehicle-related services (V2X) such as vehicle-to-vehicle (V2V), vehicle-to-infra (V2I), and vehicle-to-pedestrian (V2P) have recently gained significant attention from the cellular industry as another opportunity for LTE-Advanced technologies to be extended to support vertical industries. These technologies are expected to be specified in Rel-14. Support for V2V and V2P over D2D communication links between UEs will be specified with the highest priority, including potential resource allocation and channel estimation enhancements to support efficient and robust transmissions with low latency. In addition, provisioning of V2X services over the link between the LTE network and the UE is also within the scope of the study. Considerations include the applicability of latency reduction and multi-cell multicast/broadcast enhancements to sufficiently meet industry and regulatory requirements for V2X Preparation of 5G Cellular Communication Standards To provide a guideline for 5G technical work, ITU-R has been discussing its IMT-2020 vision in recent years and has recently finalized the IMT-2020 vision document [4]. Contrary to previous generations, which focused on enhancement of mobile broadband and improving voice or data capacity, 5G is expected to enhance three major usage scenarios, as shown in Figure 23.8(a): enhanced mobile broadband (embb), massive machine type communications (mmtc) and ultra-reliable and low-latency communications (URLLC). One example of the new services under the mmtc heading is the IoT, that will connect a very large number of objects: smart power meters, street lights, cars, home electronics such as refrigerators and

13 5G Standard Development: Technology and Roadmap 571 TVs, and surveillance cameras. The representative services of the URLLC category are factory automation, remote surgery and self-driving cars, which can be characterized by their requirement for very low latency and high reliability to prevent any accidents from happening. While mobile broadband has been enhanced quite a lot in previous generations, mobile network operators are emphasizing the importance of providing as uniform a user experience as possible regardless of where the mobile devices are located in a mobile network. It is now well understood that the energy consumption for operating mobile networks should also be reduced in order to reduce the operational cost as well as to be a good citizen to preserve the natural environment. These considerations resulted in defining the following eight parameters as key performance indicators of IMT-2020: peak data rate, user-experienced data rate, spectrum efficiency, mobility, latency, connection density, network energy efficiency, and area traffic capacity. Figure 23.8(b) shows target values for the identified parameters for IMT-2020 in comparison with those of IMT-Advanced. Following the success of standardization and commercialization of 4G technologies, 3GPP has become the only place where technical work for standardizing 5G technologies will take place. The 5G standards from 3GPP will be brought to ITU-R for official publication in 2020 with the name of IMT ITU-R agreed on the timeline and process for IMT-2020 [10] as given in Figure GPP has to finalize the standardization of 5G so that it satisfies all the requirements of IMT-2020 by the end of It must then submit the specifications of the 5G standard to ITU-R at the beginning of the IMT-2020 specifications process. Even though the official IMT-2020 specifications will be published only in year 2020, there are commercial requests to deploy the first 5G system around the year It also should be noted that there are various activities in the mobile industry to demonstrate the expected 5G technologies, for example at the 2018 Winter Olympics in Pyeongchang, Korea and the 2020 Olympics in Tokyo, Japan. In order to meet such commercial requests, it is expected that 3GPP will take a phased approach for 5G standardization. The first phase of the 5G standard, which should satisfy a part of IMT-2020 requirements, will be completed in 2018 to enable early commercial deployment around The second phase, which should satisfy all of the IMT-2020 requirements, will be finalized in 2019 for submission to ITU-R as a candidate technology for IMT To satisfy the 5G requirements, there are two candidate approaches in 3GPP: the first is to continue enhancing LTE-Advanced technologies and the second is the introduction of a new radio access technologies. LTE-Advanced was designed to satisfy IMT-Advanced requirements and its enhancement beyond Rel-13 may be able to meet a part of the IMT-2020 requirements. However, further enhancements based on LTE-Advanced to meet the more demanding IMT-2020 requirements could face significant difficulties because backwards compatibility for coexistence with legacy UEs needs to be maintained. Therefore, 3GPP will standardize a new radio access technology for IMT One of the most promising technologies for the new RAT to satisfy the drastically increased data rate requirements of providing 20 Gbps is the utilization of higher frequency bands than used in traditional cellular communication bands, say around 30 GHz. Utilization of such higher frequency bands make it easier to use a very wide contiguous spectrum of bandwidth more than 500 MHz which would be difficult to operate by carrier aggregation as is done in LTE-Advanced. It is also a common understanding that there is not sufficient frequency spectrum available below 6 GHz even though WRC-15 discussed allocaiton of additional frequency bands below 6 GHz. Due to the above considerations, there is high

14 572 Signal Processing for 5G Enhanced Mobile Broadband Gigabytes in a second 3D video, UHD screens Smart home/building Work and play in the cloud Augmented reality Industry automation Voice Mission critical application Smarty city Future IMT Self driving car Massive machine type communications Ultra-reliable and low latency communications (a) Usage scenarios of IMT for 2020 and beyond Peak data rate (Gbit/s) User-experienced data rate (Mbit/s) Area traffic capacity (Mbit/s/m 2 ) IMT x Spectrum efficiency 3x 100x Network energy efficiency 10x 1x IMT-Advantage Mobility (km/h) Connection density (devices/km 2 ) Latency (ms) (b) Enhancement of key capabilities from IMT-Advanced to IMT-2020 Figure 23.8 Usage scenarios and key capabilities of IMT for 2020 and beyond [4] level of interest in utilizing the new spectrum resource above 6 GHz, not only from mobile industries but also from governments and regional spectrum-related organizations. Therefore, it is expected that new frequency bands above 6 GHz will be allocated by WRC-19. 3GPP is expected to develop the new RAT standard to meet the IMT-2020 requirements, utilizing all frequency resources available in the traditional cellular frequency bands below 6 GHz as well as high-frequency bands above 6 GHz (up to 100 GHz). It is believed that the OFDM-based waveform will still be a baseline waveform, with potential variations, for example the application of additional filtering per subcarrier or per subband to reduce the

15 5G Standard Development: Technology and Roadmap 573 Feb Feb Jun Oct Oct Jun Oct Feb Oct IMT-2020 Evaluation criteria Requirement Proposals Evaluation IMT-2020 specifications Figure 23.9 Timeline and process for IMT-2020 overhead caused by cyclic prefix and guard bands [11 16]. In order to support such a wide range of frequency bands, there will be a need to introduce multiple numerology sets defining OFDM-based waveforms. For example, the subcarrier spacing in the 2-GHz frequency band and the 30-GHz frequency band will have to be different, since the 15-kHz subcarrier spacing of the LTE standard is too narrow to be robust against RF phase noise in a frequency band around 30 GHz. The maximum bandwidth of a carrier and the supportable FFT size will also be reasons for defining different numerologies to support different frequency bands up to 100 GHz. Even though multiple numerologies will be introduced, it will be highly desirable to keep commonality and scalability for operations in different frequency bands so that the implementation complexity can be kept reasonable. One of the main challenges for utilizing high-frequency bands around 30 GHz known as the mmwave band is the limited coverage due to large path loss. The conventional assumption is that the path loss is proportional to the frequency squared. However, the utilization of beamforming is quite useful to improve coverage. Furthermore, it is easy to have large beamforming gains in the mmwave band, since the wavelength becomes shorter as the frequency increases and there can be more antenna ports for the same antenna dimension, thereby allowing for sharper beams with higher beamforming gains. In the mmwave bands, conventional digital beamforming may not be feasible, since too many RF chains, each of which is used for each digital path, are required to support the massive number of antenna elements. In order to keep a reasonable RF complexity, a combination of analog beamforming and digital precoding the hybrid beamforming illustrated in Figure is considered a practical approach for mmwave-based systems [17 19]. The analog part forms a set of beams to make sure that the terminals in the coverage area can be connected to the network and the digital part can be used to optimize performance of communication with scheduled terminals by combining analog beams. It is expected that the new RAT may not provide full coverage in the early phases of 5G commercialization. In the case of mmwave band systems, even though the beamforming will help increase coverage, it may not be practical to assume that full coverage can be provided. This understanding motivates the utilization of LTE-Advanced and the idea that 4G base stations will give a coverage layer providing control-plane operations, while 5G base stations serve as the capacity layer the user-plane operation providing high data-rate services. This is shown in Figure 23.11, where a terminal is simultaneously connected to both 4G and 5G base stations when it is in the coverage area of a 5G base station. In order to guarantee proper

16 574 Signal Processing for 5G Digital Precoding MIMO Encoder Baseband Precoder IFFT IFFT P/S RF chains P/S DAC DAC Analog beamforming Array Ant. PA a Phase shifters Mixer MIMO Channel Figure Hybrid beamforming Figure Tight integration between 4G and 5G communication links between the terminals and the network with such split structure, it would be essential to have tight integration between 4G and 5G base stations. It is noted that if the 5G system supports full coverage, loose interworking with the 4G system may be enough. A possible phased approach to support early commercial deployment around 2020 would be that embb is optimized in the first phase and the other usage scenarios are introduced or optimized in the second phase. In order to guarantee smooth migration from the first to the second phase, the first phase standard should guarantee easy and efficient introduction of new functions in the second phase and later. Provisioning of such forward compatibility is quite important, since it is becoming more difficult to predict what services will be needed in the future, as the information technology is evolving. A practical way to achieve this goal would be to leave as much air resource vacant as possible in the new RAT; in other words, signals and channels should be transmitted only when needed to serve for communication for a specific terminal(s). For example, transmission of periodic signals such as the CRS of LTE system,

17 5G Standard Development: Technology and Roadmap 575 CRS is always transmitted LTE CRS in LTE Reference signal in 5G 5G Reference signals are transmitted only within data channels Figure An example of forward-compatible design which makes it difficult to introduce new features later, can be minimized in the new 5G RAT as illustrated in Figure Concluding Remarks In this chapter, the standards roadmap from 4G to 5G was reviewed, and major enabling technologies and a more detailed roadmap of 5G standards were discussed. 5G technologies should be developed to enable efficient support of enhanced mobile broadband, which has been the major focus of previous generations, as well as new services such as massive machine-type communications and ultra-reliable and low-latency communications. In addition to the existing cellular frequency bands up to 3.5 GHz and new bands below 6 GHz, new frequency bands above 6 GHz (up to 100 GHz) are expected to be important in developing 5G technologies, especially for support of embb. As can be seen recently, 4G technologies are having great commercial success globally. This became possible as a result of the industry momentum created through the standardization process in 3GPP, and the development of the LTE and LTE-Advanced standards, in which global manufacturers and major mobile network operators participated. Based on the industry experience with 4G, the standardization process for 5G is also expected to play a crucial role in leading research activity in 5G technologies to commercial success. References [1] Zhang, J.C, Ariyavisitakul, S., and Tao, M. (2012) LTE-advanced and 4G wireless communications. IEEE Commun. Mag., 50 (2), , [2] 3GPP (2010) TR , Feasibility study for Further Advancements for E-UTRA (LTE-Advanced) [3] METIS (2015), ICT METIS/D8.4, METIS final project report. [4] ITU-R WP-5D (2015) Document 5D/TEMP/625-E, IMT Vision Framework and overall objectives of the future development of IMT for 2020 and beyond [5] 3GPPTR (2011) Coordinated multi-point operation for LTE physical layer aspects. [6] 3GPP (2014) TR , Study on 3D channel model for LTE. [7] 3GPP (2015) TR , Study on elevation beamforming/full-dimension (FD) MIMO for LTE. [8] 3GPP (2015) TR , Study on licensed-assisted access using LTE. [9] 3GPP (2013) TR , Study on provision of low-cost machine-type communications (MTC) user equipments (UEs) based on LTE. [10] ITU-R (2015) WP-5D, Att to 5D/1042, ITU-R Working party 5D structure and work plan.

18 576 Signal Processing for 5G [11] Chang, R. (1966) High-speed multichannel data transmission with bandlimited orthogonal signals. Bell Sys. Tech. J., 45, [12] Saltzberg, B. (1967) Performance of an efficient parallel data transmission system. IEEE Trans. Commun. Tech., 15 (6), pp [13] Hirosaki, M.B. (1981) An orthogonally multiplexed QAM system using the discrete Fourier transform. IEEE Trans. Commun., 29 (7), [14] Farhang-Boroujeny,B. (2011)OFDM versus filter bank multicarrier.ieee Signal Process.Mag., 28 (3), [15] Premnath S. Wasden, D., Kasera, S., Patwari, N., and Farhang-Boroujeny, B. (2013)Beyond OFDM: best-effort dynamic spectrum access using filterbank multicarrier. IEEE/ACM Trans. Network., 21 (3), [16] Bogucka, H., Kryszkiewicz, P., and Kliks, A (2015) Dynamic spectrum aggregation for future 5G communications. IEEE Commun. Mag., 53 (5), [17] Pi Z. and Khan F. (2011)An introduction to millimeter-wave mobile broadband systems. IEEE Commun. Mag., 49 (6), [18] Kim C., Kim, T., and Seol, J.Y. (2013) Multi-beam transmission diversity with hybrid beamforming for MIMO-OFDM systems, in Proc. IEEE GLOBECOM 13 Workshop, pp [19] Roh, W., Seol, J.Y., Park, J., Lee, B., Lee, J., Kim, Y., Cho, J., Cheun K., and Aryanfar, F. (2014) Millimeter-wave beamforming as an enabling technology for 5G cellular communications: theoretical feasibility and prototype results. IEEE Commun. Mag., 52 (2),

19 CHAPTER 2 WHY IS PM IMPORTANT, ESPECIALLY IN TELECOMMUNICATIONS? Why is it necessary and even important to use project management? People who appreciate and practice project management will say that it is always important to use project management tools and techniques for projects of any level of complexity. One might then ask why they would believe this. There are many reasons. Some of the benefits of the application of project management techniques that are important for any project include: ensuring good teamwork and other people factors, meeting the project budget and schedule, producing products and work of the expected quality, effectively managing project risks, ensuring that good communication occurs, and ending the project by delivering results that include the full scope as originally planned. All of these things are aspects of management of a project and they are the factors that define success in any project undertaking. For any project, there are many factors in play. First, consider the project team, comprising the group of people actively working to deliver the product or service that the project is in place to produce. The project team is generally a multidisciplinary group; the people on the team will have different backgrounds, different objectives, and different ways of thinking. To ensure that such a diverse group can produce whatever is required will take some management focus, and that focus is one of the most important aspects of project management. TEAM DIVERSITY The team will also usually be temporary, composed of people who do not usually work together. Thus, it is very likely that they do not know each other well, creating a need for time and effort to be used to develop understanding of other team mem- ComSoc Guide to Managing Telecommunication Projects. By Celia Desmond 11 Copyright 2010 the Institute of Electrical and Electronics Engineers, Inc.

20 12 2 WHY IS PM IMPORTANT, ESPECIALLY IN TELECOMMUNICATIONS? bers, to ensure that people will understand what is needed to work with the other members of the team. Given the multidisciplinary aspects of the project team, we can see that considerable management effort will be needed to understand the diverse points of view of the people assigned to the project, building a team that will work together well and with effective communication to achieve the project goals. Again, this skill is part of project management. In any project, the people on the team need to evaluate their own environment, their own project, their own skills, and their own company. Based on factors such as these, they can decide how they can best work with the rest of the team to produce the best quality product or service possible. RESOURCE LIMITATIONS Another characteristic of projects is that there are usually hard limits to the budget and other resources required to implement the project. Thus, there will be a need to prioritize just how and on which components the money should be spent, which is again a component of project management. TIME CONSTRAINTS AND LIMITATIONS Time is always an important factor for the project manager. Since projects take people away from their regular jobs, there will be time pressure to return the people to their own organizations, even when there is little time pressure to make the project s product or service available by a specific time. However, most projects start with schedule constraints already in place, so time management, another key component of project management, is also a crucial skill. Any team will be better equipped to meet both time and cost targets if these are clear, reasonable, understood, and well communicated. RISK MANAGEMENT The understanding and management of risks is crucial to the project manager. Considering all of the above factors of the project environment people working with others they do not know on multidisciplinary teams to produce something that is initially not well defined and outside the normal work framework, with time and money pressure would it be reasonable to expect that the environment for any project is not risky? Obviously, skill in risk management is always needed. ENSURING QUALITY What about quality? Projects are undertaken to take advantage of business and technology opportunities to introduce a new product or service. In most cases, a new

21 SCOPE DEFINITION 13 product or service displaces something else that had previously met the needs of the targeted market. The quality of the new product or service is often the factor that will allow it to compete well with the previously established competing product or service. To make the new product or service of the best possible quality, it should be produced using quality-management techniques. Quality management, therefore, is another important aspect of project management. SCOPE DEFINITION One of the most important aspects of project management is the understanding, clear definition, and effective management of the project scope. Consider the nature of a project, which is to produce something unique. The output of a project is often not something that people already know and understand. In the case of ongoing work in a normal production environment, it could be quite reasonable to expect that people understand what needs to be done and what is to be produced. But at the outset of a project, it is very likely that no one except possibly the project sponsor and the project manager has a very good understanding of what is to be produced, let alone how to achieve this. In most cases, quite a lot of work is required to clearly define the required output and the work needed to allow this to be provided. Scope definition and subsequent management is a large part of project management. One of the Project Management Institute project management process areas is scope management, and within this area there are processes and tools that are used to clearly define the scope of the project and to manage proposed changes. It takes just common sense to realize that any project team can avoid mistakes by ensuring that all those involved with the project, either as workers, managers, or receivers of the product, have a common understanding of what it is that the project will deliver, and it would be even better if they all had the same understanding of how the production of this end product would be done. Once the project scope has been defined and approved, and the rest of the planning has been done, project implementation begins. At that point, the scope, the team, the schedule, the budget, and other project parameters have been set. After this point, if changes are needed, there is potential for this change to impact many aspects of the project. Such proposals for change are called scope changes. There has never been a project that did not have changes to scope. Some huge projects have experienced literally thousands of changes to scope. For the most part, people do not propose scope changes for the sake of the change itself; there is generally good reason for wanting the change. And in some cases, it makes much more sense to implement the change than to not go ahead with it. But, making any change impacts the project, and too many of these can cause a project to fail, no matter how well everything else is done. Scope change requests come in many forms. In one form, someone (usually the customer) says, Just add this little feature. It only costs a little bit more, takes a lit-

22 14 2 WHY IS PM IMPORTANT, ESPECIALLY IN TELECOMMUNICATIONS? tle more time, and everything will be 100 times better. That might be true and it might well be much better to incorporate the small change now, while there are people geared up, equipment in place, and so on, than to go ahead without doing it and try to incorporate it later, outside of the project. It might be possible to do one, or two, or three such additions that will cost little in time and/or money, but when the number of these requests gets to ten or a hundred, there is no way within the time frame and budget, and with the people on the project team, that these can be accomplished. Let us be ultraconservative and suppose that each proposed scope change was accepted and the time required to complete each one was only one person-hour. Most people will think, rightly, that expecting each request for change to take only one person-hour to implement is unrealistic, as scope changes often take weeks or months to accommodate. But for this example, suppose each one only took one hour. If we had 1000 requests for tiny changes, which is not really unexpected in, say, a project with a team of 50 people running for, say, 18 months, accepting all of these requests would mean adding 1000 person-hours to that project. That s an addition of 125 eight hour days to the project, or more than an additional four-person months. And if this project received three times this many requests, which is not all that unusual in some environments, we would need an additional person-year to complete just the things that were not in the initial plan if none of them took more than one hour to complete. But of course, most take far more than a short time to complete, and every project receives these requests, usually many of them, so there needs to be some time included somehow to do these unplanned items. Therefore, in order to be able to meet the schedule and the budget, it is necessary to incorporate some mechanisms that will allow the project team to deal with the many change requests that will inevitably arrive. These need to be considered, assessed, and either accepted or rejected, and, regardless of the decision, the impacts of that decision must be dealt with. All of this will take time, and time costs money. So a change request process is a very important component of project management, and one which is needed for every project. In another situation, the change request arrives via a statement from one of the team members that there is a design flaw in the project or the product to be produced, and unless this is fixed the whole project will be down the drain. It just will not work. This is quite different from someone thinking up a new addition that would be nice to have. This one, if the requestor is correct, is necessary if the project is to be successful. But it is still a change to the project scope, and making the change will cost time and money, not to mention the possibility of needed additional skills or a new risk to the team. The change must be accepted, but this should not be done lightly. Good project management practice requires that this proposed change go through the change request process, and if accepted, be implemented only once all the impacts are understood and the required resources have been obtained. In short, every project will experience proposals for changes to the initially planned scope. And these changes do interfere with projects. A few smaller ones

23 PROJECT OBJECTIVES 15 might be incorporated by having people work a little harder, or some such mechanism, but, overall, if you take on many changes, or large ones, the project will not finish on time, with the right quality level of product, at the right budget. Well-defined project management techniques help the project manager be clear on what factors the team, and the project manager himself, is being measured. Quite possibly, one s bonus for the year, or even keeping one s job, depend on projects finishing on time, on budget, or with some specific deliverables working well. If as a project manager you keep taking on more work without ensuring that compensating budget or schedule changes are put in place, failure is inevitable. Every project undergoes scope changes; we know before the project starts that these requests are going to come, so it only makes sense to plan for them. PROJECT OBJECTIVES Another aspect of project planning is the setting and communication of clear, attainable, and measurable objectives. Doing this can avoid frustration by ensuring that the team members and the key stakeholders all march to the same drummer. A team will be better able to ensure that all those involved with the project in any way have the same expectations and the same information if there is good communication, especially agreed-upon formal communication. But communication does not just happen: proper communication requires planning and focus, both of which are skills of the good project manager. With the right attention by all team members who have something useful to contribute, decisions can be made consciously and for the right reasons. It is part of the project manager s role to ensure that this will happen. With the right communication, it is easier for the team to avoid known pitfalls, even for a fairly straightforward project. Consider the following example of organizing an IEEE conference. In a volunteer organization such as IEEE, typical projects might be the organization of conferences, whether small ones of only attendees, or large ones attracting thousands of people. Such projects include the preparation of publications with papers by many authors; the initial request for these papers; receipt and review of the papers; organization of the papers into sessions with a technical theme; the organization of meals and coffee breaks; the organization of events such as receptions; providing speaker instructions or awards presentations; the making of hotel arrangements, and, possibly, conference center arrangements so that attendees will have a place to stay and sessions can be held; the publicizing of the event; and so on. Obviously, these functions are not all carried out by only one or two people, so there is a requirement that there be good communication amongst the organizers. The rooms need to be the right size for the sessions, and the conference needs to have enough rooms. The attendees need to have the information about the conference, how to register, where it will be held, when and where to attend the sessions,

24 16 2 WHY IS PM IMPORTANT, ESPECIALLY IN TELECOMMUNICATIONS? and so on. So not only must there be good communication amongst the organizers in each area, there must be good communication amongst the organizers of the different aspects of the conference, and excellent communication with potential and confirmed conference attendees, to attract people and ensure that they get the most out of the conference. The people doing the organization are all volunteers. They work for different companies and frequently live in different countries, yet they must work together to make the conference happen smoothly. This can be done only with strong, planned, well-organized communication. Another quite different volunteer project is our example of the Communications Society Wireless Communications Engineering Technologies Certification, for which the team has over 100 members. This project again has not only a large team, but people working in very diverse areas and roles within the project, and these people live in over 20 countries around the world. Although it is not necessary for each of these people to communicate directly with all of the others, it is clear that the certification cannot be developed efficiently or successfully without strong, planned, organized communication amongst the team members, and a great deal of it, for a successful outcome. In volunteer work, project teams are made up of people who work for companies, self-employed entrepreneurs, and academics, who frequently live in many different countries around the world. These people agree to do the volunteer work in addition to their own workload, for no monetary compensation. The project manager does not have any control over the people in a volunteer organization. These people are working on the project because they want to be there, and if they do not feel like providing their deliverables until the last minute or submitting a status report, they do not have to. And unless the project manager can influence the people positively, some of the material needed for the project will not meet requirements. Today, similar situations often exist in electronic communications projects within for-profit companies. The team members are not volunteers, but they may be working in environments that are as diverse as those described here and they could well also work for different companies that are cooperating to build a joint product or service. Managing projects for volunteer work is different from doing so at work, where the project manager has a degree of defined authority. But even in work situations in which project managers have control over all the people on their teams, generally they do not have control at all over most of the project stakeholders. Project managers do not always directly supervise the people that are working on the project. In some management structures, the project manager is more of a coordinator, and does not directly supervise any of the team members. The team members continue to report to their usual supervisors, but are assigned project work instead of, or in addition to their regular job. The project manager is charged with overseeing the project work and making sure that it all happens according to the project needs and plan. That means that it is up to the project manager to use relevant skills, not the limited authority associated with the project manager title, to get people to do things, to get them done well, and to get them done on time.

25 WHAT ABOUT TELECOM PROJECTS? 17 WHAT ABOUT TELECOM PROJECTS? The title of this chapter emphasizes the importance of project management for telecommunications projects. So far, the discussion has been about the importance of project management for projects in general, with no specific reference to telecommunications projects. This book focuses on the application of project management principles to telecommunications-related projects. It is more important to use proper project management technique in telecommunications than in most other sectors due to some particular characteristics of the industry. Consider the type of projects that typically occur in the telecom industry. Many of these involve huge networks, either for a provider or a large end user, or extremely complex services and equipment, with hardware, software, business, and integration aspects. Teams tend to be large from 25 to hundreds of people per project and the technologies involved are extremely complex. Project management lends itself well to handling such size and complexity. Most significantly, in this rapidly changing industry, many companies find themselves needing to do things for the first time, and handling these situations by implementing projects is often the only practical way of accomplishing this. Telecommunication technologies involved in projects are usually fairly new (and, therefore, not well known), and there is a requirement in many cases for interworking of many different technologies. All of this creates a requirement for significant technical knowledge on the team, and, generally, also significant business or marketing knowledge, making it necessary that the teams be multidisciplinary and competing for people with scarce and valuable skills and experience. The application and interworking of new technologies ensures that telecom projects will contain a higher than average degree of risk. This unpredictability implies that there will be challenges in defining the project scope accurately, in turn making timelines and budgets hard to nail down. All of this adds up to a need for strong and ingenious project management. Telecom projects are planned and implemented in an environment that experiences continuous, significant, and rapid changes. The following is a view of several aspects of the telecommunications industry that are important to the application of project management in this sector. Technologies Whether we look at access, transmission, switching, terminal devices, service platforms, servers, billing, provisioning, ordering testing, or any aspect of telecommunications products or services, we find very many technologies in use. These are at various stages of development, and they all must interwork with each other and with applications that customers create, such as local area networks. Consider access technologies. These could include copper pairs, video cable, wireless, or fiber optics. And if we take just one of these technologies, say wireless, there are probably no less than 15 different versions of this technology that might come into play

26 18 2 WHY IS PM IMPORTANT, ESPECIALLY IN TELECOMMUNICATIONS? in some way in a project, including WiFi, WiMax, satellite, Bluetooth, and ultra wideband. Some projects do not involve more than one of these, while others might involve many. But almost all telecom projects do include at least one relatively new and rapidly evolving technology, resulting in an unstable project environment. Thus, there is a very great need for technical skills that must be developed and kept current as the project evolves, placing more stress on the project than there is in other industries in which the technologies are less complex and more static. Services In this book, we discuss the changing nature of the services offered today, as the Internet and entertainment media become integral to electronic communications services. Whereas for many years a telecom service involved mainly local voice service or long distance voice service, with possibly a separate data component, today s services need to be built by integrating voice, data, and multimedia in innovative ways in order to be successful. The requirements for such projects are much more complex than they have been in the past for telecom services, since the need for innovation creates higher risks, as does the integration of the many different components. Customer expectations of new services are escalating very rapidly. Capabilities that were considered close to miraculous five years ago are now considered outdated and of little interest. It is extremely difficult, despite the efforts of armies of marketers, to predict what service will be a hot item months in the future. So the risk is high, and the teams of people from many different areas must work together in order to introduce successful service offerings. Companies in the Business In the previous chapter, we talked about the rate at which competition is escalating in electronic communications and the many different companies that are now providing these services. Projects are put in place to either take advantage of opportunities or create solutions to problems. These opportunities and problems occur in an environment that is ever changing, where competing companies may create market or operational pressures that impact the project, the project work, and the project outputs. If the home company of a project merges or becomes acquired, the nature of the project is often affected. When a new competitor appears with products that are new, better, or different, priorities of the project change. So the evolution of the companies in the relevant business sector places a heavy strain on the project teams working to provide services and products for telecommunications. Regulatory Environment Over the past years, the level of regulation governing telecom has been gradually decreasing in most areas. However, many things are still regulated, and some

27 WHAT ABOUT TELECOM PROJECTS? 19 are heavily controlled. Once regulations are set and understood, they place requirements on the project that must be incorporated into the project requirements along with any other requirements. Project teams often need to work during intervals when regulatory changes are expected or threatened, without knowing what the situation will be at some point in the future. This greatly increases the project risk, and also the stress on the project team, creating a need to manage toward the most optimal solution. Successful Business Model Since the inception of the telecom technologies and business, the industry has operated under similar business models in most countries. These business models have been based on the premise that the customer pays for the service delivered. Sometimes the models were usage based, and in other cases the payments were flat rates, usually monthly. In some cases, the customer pays for both outgoing and incoming calls, whereas in other cases only outgoing calls are charged. When there is a need for equipment beyond that used for standard service, the customer might either lease or purchase the additional equipment. Today, for many services these traditional models do not apply. Instead, the services are sometimes offered free, with advertisers paying the cost, with rates depending on the popularity of the services. Thus, in addition to the need for more innovation in the development of new services, the teams often also have to deal with a new business model. This again makes the environment more risky, increasing the need for good project management. Internal Corporate Structures Yet one more issue that teams face during today s projects is the internal restructuring of their companies, moving from highly hierarchical structures to ones that are flatter, or from structures based on older services such as local, long distance, and cellular to structures based on models of newer services, such as video or social networking. The team then is essentially standing on a rolling platform while they work on the project. This raises the stress level of the people on the team, including, of course, the project manager. People will dilute their focus on the project as they watch the developments in their company, increasing the pressure for the management of the project. Customers Given that competition is rampant today, customers have to deal with more choices and the anxieties they bring with them. They do not know with any certainty which company to buy from or which offer to take. If the project is providing a product or service for outside customers, there is a need that is becoming more important for

28 20 2 WHY IS PM IMPORTANT, ESPECIALLY IN TELECOMMUNICATIONS? telecom projects that of understanding the perspective of the potential customers and even determining what emerging entity might become a potential customer. This is an increase in the scope of projects above that experienced in this industry in the past requiring new skills and teams to deal with new perspectives. This, in turn, creates more need for team building, for clear understanding of the project scope, and for communication of this changing information to the project team. All of these are again components of the project manager s job. The Best Way to Market Customer needs are changing, as are business models. Even the types of services and products that should be offered are not what they used to be. There is also a need to for the project team to understand how to build marketing plans, and how to best approach the market. This again extends the skills needed and the number of perspectives the team must consider. Service Models Telephone services have been highly controlled in the past, in the sense that the intelligence that makes the service work, and the control of the network, its traffic, and all of its operating parameters have been all completely in the hands of the providing company. Traditional companies are very protective of these services, and their control, but this way of doing things is becoming less dominant in the telecom industry. Newer services use open platforms, and often contain components provided and built by multiple providers. Network intelligence and control is no longer solely resident in the core of the network and, in fact, much of the control resides at the edge. Rather than a service being delivered in its entirety by a single service provider, it is now often delivered by a loose partnership of specialized companies. This, of course, increases the risk that the service will not work well, and the pressure on the architects of the network to know, understand, and work with multiple technologies and providers. Again, this is one more pressure on the project, and one more reason that management is needed. Network Architecture In the previous chapter, we discussed the evolution of telecom networks from circuit-switched systems connected via TDM facilities to packet-switched networks running Internet Protocol. This change of the technical environment in which new projects are implemented from that which many team members know drives a need for constant learning on the part of the team members to keep current. Inability to do so reduces the technical effectiveness of the team, adds risks due to the higher probability of wrong decisions arising from unfamiliarity with the technology, and also can seriously impair the self-confidence of the team members, leading to per-

29 CONCLUSION 21 sonal stress and highly risk-averse behavior. Identification and implementation of the necessary training should be a factor in the planning of the project. CONCLUSION It is clear that the skills, technical and otherwise, required to effectively complete a telecom project today are more varied than those that have been needed in the past. Summing up all of the variables discussed in this chapter and in the previous one, we see that many, many things are evolving and changing, and the sum of all these changes is a very volatile environment in which to do projects. Because of the degree of change encountered in the telecommunications industry, the need for project management is much greater than in many other sectors. Electronic communications project teams are operating with a high degree of change in many areas, and these must be well understood when planning, designing, and implementing projects: Changing business environment Increased level of competition Accelerated project schedules Unfamiliar new technologies New business models with integration aspects outside the control of the team Change-driven personal stress effects on team members and other stakeholders High costs for evolution of networks in a era of tight budgets Importance of communications is escalating a core process for project teams Some degree of project management is needed for any project, and the more complex the project, the greater the need for the management and the more formal the processes become. Telecom projects are more complex by far than most other projects, and they are also generally larger. Both of these factors increase the demand for project management in order to enhance project success. Projects in telecom occur today in environments dealing with rapid change, and many widely different aspects of the project environment are changing as the projects proceed. Even one of these changes would be significant justification for strong management of projects. But in the electronic communications environment, many of these diverse changes are operating in parallel, so if project management is needed anywhere, it is needed desperately in today s telecommunications industry.

30 CHAPTER 10 PERSONAL PROTECTION (SAFETY) CHAPTER OBJECTIVES After completing this chapter, the reader will be able to: Discuss Personal Protection Equipment used for safety in electric power systems Explain human vulnerability to electricity Explain how one can be safe by Isolation or Equipotential Discuss Ground Potential Rise and associated Touch and Step potentials Discuss how Energized or De-energized and Grounded lines provide safe working environments for field workers Discuss the Safety Hazards around the home ELECTRICAL SAFETY The main issues regarding electrical safety are the invisible nature of hazardous situations and the element of surprise. One has to anticipate, visualize, and plan ahead for the unexpected and follow all the proper safety rules before an accident to gain confidence in working around electricity. Those who have experience in electrical safety must still respect and plan for the unexpected. There are several methodologies and personal protective equipment (PPE) available that make working conditions around electrical equipment safe. The common methodologies and safety equipment are explained in this chapter. The theories behind those methodologies are also discussed. Having a good fundamental understanding of electrical safety principles is very important and is effective in recognizing and avoiding possible electrical hazards. There are two aspects of electrical safety that are discussed in this chapter; electric shock or current flow through the body and arc-flash or being burned by the heat created by an electrical arc when equipment failure occurs. Protection against electrical shock is discussed first. Electric Power System Basics for the Nonelectrical Professional, Second Edition. Steven W. Blume by The Institute of Electrical and Electronics Engineers, Inc. Published 2017 by John Wiley & Sons, Inc. 209

31 210 ELECTRIC POWER SYSTEM BASICS FOR THE NONELECTRICAL PROFESSIONAL PERSONAL PROTECTION Personal protection refers to the use of proper clothing, insulating rubber goods or other safety tools that provide electrical isolation from electrical shock. Another form of personal protection is the application of equipotential principles, where everything one comes in contact with is at the same potential. Electrical current cannot flow if equipotential exists. Either way, using insulating personal protection equipment (PPE) or working in a zone of equipotential are known methods for reliable electrical safety. Human Vulnerability to Electrical Current Before discussing personal protection in greater detail, it is helpful to understand human vulnerability to electrical current. The level of current flowing through the body determines the seriousness of the situation. Note, the focus is on current flow through the body opposed to voltage. Yes, a person can touch a voltage, create a path for current to flow, and experience a shock, but it is the current flowing through the body that causes issues. Testing back in the early 1950s showed that a range of about 1 2 ma ( A) of current flow through the human body is considered the threshold of sensitivity. As little as 16 ma (0.016 A) can cause the loss of muscle control (lock-on). As little as 23 ma (0.023 A) can cause difficulty breathing, and 50 ma can cause severe burning. These current levels are rather small when compared to normal household electrical load. For example, a 60 W light bulb draws 500 ma of current at full brightness with rated voltage of 120 V. The residential ground fault circuit interrupter (GFCI) like those used in bathrooms (discussed earlier) open the circuit if the differential current reaches approximately 5.0 ma (0.005 A). The GFCI opens the circuit breaker before dangerous current levels are allowed to flow through the human body. The conclusion is humans are very vulnerable to relatively small electrical currents. Principles of Isolation Safety A person can be safe from electrical hazards through the use of proper rubber isolation products, such as gloves, shoes, blankets, and mats. Proper rubber goods allow a person to be isolated from touch and step potentials that would otherwise be dangerous. (Note, touch and step potentials are discussed in more detail later in this chapter.) Electric utilities test their rubber goods frequently to insure that safe working conditions are provided. Rubber gloves are routinely used when working on de-energized high-voltage equipment just in case it becomes accidently energized. Rubber gloves are also used for hot-line maintenance at distribution voltage levels only. Figure 10-1 shows the cotton inner liners, insulated rubber glove, and leather protector glove used in typical live line maintenance on distribution systems or to protect against accidental energization.

32 PERSONAL PROTECTION (SAFETY) 211 Figure 10-1 Rubber gloves. Courtesy of Alliant Energy. Figure 10-2 shows high-voltage insulated boots. Figure 10-3 shows typical high-voltage insulated blankets and mats. Every electric utility has extensive and very detailed safety procedures regarding the proper use of rubber goods and other safety-related tools and equipment. Adherence to these strict safety rules and equipment testing procedures insures that workers are safe. Further, electric utilities spend generous time training workers to work safety, especially when it comes to live line activities. Principles of Equipotential Safety Substations are built with a large quantity of bare copper conductors and ground rods connected together and buried about inches below the surface. Metal fences, Figure 10-2 Insulated boots.

33 212 ELECTRIC POWER SYSTEM BASICS FOR THE NONELECTRICAL PROFESSIONAL Figure 10-3 Rubber blankets and mats. Courtesy of Alliant Energy. major equipment tanks, structural steel, and all other metal objects requiring an electrical ground reference are all connected to the buried copper conductors. This elaborate interconnected system of conductive metals form what is referred to as the station ground grid. This elaborate ground grid provides a safe working environment that is sometimes referred to as equipotential grounding. Usually a copper conductor is buried outside the fence perimeter (approximately 3 feet from the fence) to extend the ground grid for additional safety. Usually 2 4 inches of clean gravel is placed on top of the soil in the substation to serve as additional isolation from current flow and voltage profiles that could exist in the soils during fault conditions. Figure 10-4 shows the ground grid concept. There are two main reasons for having an effective grounding system; first, to provide a highly effective ground path through earth soil for fault current to flow back to the source in order to trip circuit breakers (i.e., system protection). Second, effective grounds provide a zone of equipotential for safe working environments (i.e., personnel protection). The effective ground grid causes high fault currents to trip Lightning or power fault Lightning rods Ground grid wires Ground rods Figure 10-4 Substation ground grid.

34 PERSONAL PROTECTION (SAFETY) 213 Ground grid Ground potential rise Figure 10-5 Substation ground potential rise. circuit breakers faster. The zone of equipotential minimizes the risk of someone experiencing a current flow during a lightning strike or power fault. Theoretically, everything a person touches in a zone of equipotential is at the same voltage and therefore no current flows through the person. As an example, suppose you were in an airplane flying above the earth at 30,000 feet. Everything inside the airplane seems normal. The same is true in a properly designed substation when a 30,000 V ground potential rise occurs. Ground Potential Rise When a fault occurs on a power system, a ground potential rise (GPR) condition occurs where high electrical currents flow in the earth soil creating a voltage profile on the earth s surface. This voltage profile decays exponentially outward from the fault location as shown in Figures 10-5 and This GPR condition can cause dangerous touch and step potentials. The following drawings show the GPR and touch and step potentials. Touch Step Figure 10-6 Distance from fault Touch and step around structures.

35 214 ELECTRIC POWER SYSTEM BASICS FOR THE NONELECTRICAL PROFESSIONAL Touch and Step Potentials During a lightning strike or power fault event in a substation, the entire substation rises to a high potential and anyone standing on the ground grid during that event should experience no touch or step potential because of the equipotential grounding. Touch potential is the difference between the voltage magnitude of a person (or animal) touching an object and the magnitude of voltage at the person s feet. Touch potential can also be the difference in voltage between two potentials (i.e., hand to hand). Step potential is the difference in voltage between a person s (or animal s) feet. Shoes, gloves, and other articles of clothing help insulate a person from touch and step potentials. Approved, tested, and properly used rubber safety products (PPE) provide isolation from potentially hazardous touch and step potentials. Working Transmission Safely Construction and maintenance crews work on power lines under-energized and deenergized conditions. Either way, special safety precautions are mandatory. All safety precautions fall back to the basic principles of either being fully isolated from electric shock or be in a zone of equipotential. One has to plan on the possibility of a deenergized line becoming accidently energized without notice. Following are examples of different ways to work on power lines safely. Energized Equipment There are multiple ways to work on energized power lines safely; insulated bucket trucks, the use of fiber glass non-conductive hot sticks and bare hand live line maintenance are the more common means. Insulated Bucket Trucks Working out of insulated bucket trucks is a means of working on lines that are either energized or de-energized. Depending on the system voltage being worked on, rubber gloves, fiber glass hot sticks, or live line bare hand methods can be used safely by working out of insulated trucks. Figure 10-7 shows using an insulated truck Hot Stick Live Line Maintenance Work can be performed when the lines are energized using hot sticks. Figure 10-8 shows workers using fiberglass hot sticks to perform maintenance. Bare Hand Live Line Maintenance A person can be placed in a conductive suit and touch energized transmission voltages as shown in Figure 10-9 as long as they do not come in contact with grounded objects. This is like a bird sitting on the wire. The conductive suit establishes a zone of equipotential and thus eliminates current flow inside the suit or human body. Since everything the person touches is at the same potential, no current flows through the body and the person is safe from electrical shock. (Picture of author touching live 345 kv)

36 PERSONAL PROTECTION (SAFETY) 215 Figure 10-7 Insulated buckets. De-energized Equipment and Grounded During de-energized conditions, workers apply ground jumpers to avoid dangerous potentials, should the line become accidentally energized. Grounding equipment serves two purposes: 1. Grounding establishes a safe zone of equipotential similar to substations. It provides a safe environment against touch potentials. 2. Grounding helps trip circuit breakers faster, should the line become accidentally energized. Figure shows several jumpers on a rack waiting to be used on a power line or substation. Working Distribution Safety Similar to transmission line work, distribution line crews work under-energized or deenergized conditions also. Special safety procedures are mandatory in either situation. Distribution line crews work energized lines (normally under 34 kv) using rubber isolation equipment (PPE) (i.e., rubber gloves and blankets) for voltages less than

37 216 ELECTRIC POWER SYSTEM BASICS FOR THE NONELECTRICAL PROFESSIONAL Figure 10-8 Live maintenance transmission lines. Figure 10-9 Bare hand live line maintenance.

38 PERSONAL PROTECTION (SAFETY) 217 Figure Ground jumpers. usually 34 kv. Figure shows live line maintenance activities on distribution systems. Working lines de-energized requires ground jumpers as discussed earlier. Switching Switching is the term used to change the configuration of the electric system or to provide isolation for safe working activities on equipment, such as maintenance. Switching is required to open or close disconnect switches, circuit breakers, etc. for Figure Live maintenance distribution. Courtesy of Alliant Energy.

39 218 ELECTRIC POWER SYSTEM BASICS FOR THE NONELECTRICAL PROFESSIONAL Figure Live maintenance substations. planned maintenance, emergency restoration, load transfer, and equipment isolation. Figure shows a switching event in an energized substation. Switching requires careful control of all personnel and equipment involved. This usually requires radio, phone, or visual communication at all times for safety assurance. Detailed radio and equipment tagging procedures are also required to help prevent others from interfering with work activities. Switching can be very time consuming due to the repetitive nature of the communication of the switching orders. ARC-FLASH Electrical arc-flash hazards are serious risks to worker safety. On the average, every day in the United States, five to ten people are sent to special burn units due to arcflash burns. The National Fire Prevention Association (NFPA) published NFPA 70E, the standard for Electrical Safety in the Workplace, in order to document electrical safety requirements regarding arc-flash safety. 70E defines specific rules for determining the category of electrical hazards and the PPE required for personnel working in defined and marked hazard zones or boundaries. OSHA enforces the NFPA arcflash requirements under its general rule that a safe workplace must be maintained. These regulations are forcing employers to review and modify their electrical systems and work procedures to reduce the arc-flash hazard and to improve worker awareness and safety. Industry regulations and standards now require the electrical equipment owner to do the following: Assess whether there are arc-flash hazards Calculate the energy released by the arc, if or when present Determine the flash protection boundaries

40 PERSONAL PROTECTION (SAFETY) 219 Provide appropriate PPE for personnel working within the flash protection boundary Provide a safety program and training with clear responsibilities Suitable tools, in addition to PPE for a safe workplace Equipment labels indicating the minimum protective distance, the incident energy level, and required PPE for that location Employees too have an obligation to arc-flash safety. They must follow the requirements of arc-flash labeling by wearing the proper PPE and use proper safety tools provided by their employer. Further, they must not work on or near electrical circuits or equipment unless they are qualified workers. About the Arc An arc-flash is the light and heat produced from an electric arc when supplied with sufficient electrical energy that can cause substantial damage, harm, fire, and/or serious injury. Electrical arcs, when controlled, produce a very bright light and when controlled, can be used in arc lamps (having electrodes), for welding, plasma cutting and other industrial applications. When an uncontrolled arc forms at high voltages, arc-flashes can produce deafening noises, supersonic concussive-forces, super-heated shrapnel, temperatures far greater than the sun s surface, and intense high-energy radiation capable of vaporizing nearby materials. Arc-flash temperatures can reach or exceed 35,000 F (19,400 C) at the arc terminals. The result of the violent event can cause destruction of equipment, fire, and injury not only to an electrical worker but also to bystanders. Figure shows what happens after an arc-flash event. Figure Arc-flash. Reproduced with permission of from LSelectric.

41 220 ELECTRIC POWER SYSTEM BASICS FOR THE NONELECTRICAL PROFESSIONAL Hazard Categories NFPA 70E includes hazard categories that take into account human vulnerability factors and the capability of available PPE clothing used to protect humans that are exposed to arc-flash incidents. Calories/cm 2 is the reference used in arc-flash criteria. One calorie/cm 2 can be equal to holding your finger over the tip of a flame of a cigarette lighter for one second. Specifically, one calorie is the amount of heat needed to raise the temperature of one gram of water by 1 C. Further, thermal energy is rated in calories/cm 2. A second-degree burn requires approximately 1.2 cal/cm 2 for more than one second. Below are the categories used in arc-flash rules and regulations. These categories correspond to required PPE. Category 0: Up to 1.2 cal/cm 2 Category 1: cal/cm 2 Category 2: cal/cm 2 Category 3: cal/cm 2 Category 4: cal/cm 2 Over 40 cal/cm 2 : Unacceptable risk Protective Clothing and Equipment Personal protective equipment (PPE) is the common term used for clothing and equipment to protect electrical workers performing activities on or near energized high-voltage equipment. In the case of exposure to arc-flash hazards and depending on the hazard risk category (defined by NFPA), PPE is primarily made up of flame resistant (FR) clothing. FR clothing is the most common and industry accepted PPE to protect the body from burns due to flame. It is not, however, designed to isolate the worker from electrical contact. The beneficial characteristic of FR clothing is that it will not continue to burn on its own when a flame source is removed. This protection is achieved by treating the fiber cloth with flame retardant modacrylic blended cottons. Table 10-1 shows the required FR PPE required for the various hazard/risk categories. TABLE 10-1 Hazard/Risk Category Required Flame Retardant Clothing Eye Protection, Ear Canal Inserts, Long Sleeve Shirt and Pants Arc Rated Clothing Face and Head Protection Flash Suit Hood

42 PERSONAL PROTECTION (SAFETY) 221 Figure Arc-flash clothing. Reproduced with permission of from LSelectric. In most applications, clothing and PPE must be either FR rated or arc-flash rated. The electrical worker should never wear materials such as nylon and polyester that can melt and stick to skin. Note non-fr-rated undergarments may catch fire even when arc rated clothing is worn overtop and survives an arc-flash. Although some of this clothing and equipment appears to be bulky, restraining, and cumbersome, manufactures try hard to add flexibility, light weightiness, and durability in their FR clothing while meeting the strict arc-flash requirements. Figure shows the clothing required for Category 4 energy. The arc rating of the FR material is the maximum incident energy resistance demonstrated by a material prior to break open (a hole in the material) or to pass through and cause a second- or third-degree burn with 50% probability. Arc rating is normally expressed in cal/cm 2 (or small calories of heat energy per square centimeter). The tests for determining arc rating are defined in ASTM F1506 Standard Performance Specification for Flame Resistant Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards. Approach Boundaries Based on the hazard categories stated earlier and the PPE flame retardant capabilities, NFPA 70E also stipulates four arc-flash approach boundaries that must be known and observed. Figure shows these approach boundaries.

43 222 ELECTRIC POWER SYSTEM BASICS FOR THE NONELECTRICAL PROFESSIONAL Figure Arc-flash boundaries. Flash protection boundary (outer boundary) is where a worker is exposed to a curable second-degree burn if outside this boundary. Limited approach boundary is the closest area an unqualified person can safely stand. Still requires PPE. A person must be qualified to go any closer. Restricted approach boundary is the closest a qualified person can stand, provided they have an approved plan for the work to be performed and it must be absolutely necessary to work in this area. Prohibited approach boundary (inner boundary) is considered the same as making contact with the energized part. Requires qualified person with specific training to work on energized conductors, appropriate PPE, and documented plan with justification. As you can see, electrical workers are required to work safely using proper PPE for both electrical contact and arc-flash hazards. All industries have their hazards; the electrical industry has these two concerns. Proper training, safety equipment, and having the proper understanding of the hazards before a live contact or arc-flash event occurs provide electrical workers with the necessary situational awareness, tools, and assurance that a safe working environment is provided. ELECTRICAL SAFETY AROUND THE HOME Home safety also involves the awareness of touch and step potentials, arc-flash too. Whether one is exposed to a dangerous touch or step potential in a substation or at home, the same circumstances exist and the same precautions are necessary. As soon as the insulation around energized wires is compromised, dangerous step and touch potentials can exist, plus a bright arc-flash event can occur if and when frayed insulated conductors touch.

44 PERSONAL PROTECTION (SAFETY) 223 Figure Safety at home. Reproduced with permission of Photovault. Figure GFCI receptacle. Reproduced with permission of Photovault. For example, worn extension cords can have exposed conductors that can cause 120 Vac touch potential hazards. All worn cords must be replaced. To compound the problem, water, moisture, metal objects, and faulty equipment can increase the possibility of injury from accidental contact. Everyone is vulnerable to electrical current, therefore always be vigilant about electrical safety at home! Figures and show how electrical safety starts at home. Reproduced with permission of Photovault. Always be vigilant about electrical safety at home!