Mobile WiMax: Description and Deployment

Transcription

1 Mobile WiMax: Description and Deployment Dr. Zulfiquar Sayeed Alcatel Lucent Bell Labs

2 Outline The big picture Specifications family OFDM and OFDMA fundamentals Profiles System architecture, handoff, QoS Summary 2

3 The Big Picture Personal Unlicensed Device Connectivity Fixed Licensed and Unlicensed Networking Portable Licensed and Unlicensed Wireless Services Mobile Licensed Broadband and Wideband Services Device to Device Device to Peripherals Campus Networking Access & Backhaul Zonal Nomadic Low Mobility Cellular WAN WPAN WPAN x WiFi WiMAX d WiFi WiMAX e WiMAX e 2.5G, 3G Coverage WPAN < Coverage WLAN < Coverage WMAN < Coverage WWAN Source: Intel Corp/ Modified 3

4 Zones of Interest of the IEEE Internet Protocols Bridging and Network Management Logical Link Control Handoff MAC + PHY Ethernet Wireless PAN New TGs Wireless LAN New TGs Wireless MAN E Mobility MBWA Mobility 2.5G 3G Oval heights signify coverage e b a/g to 200 kbps 200k to 1Mbps 1M to 10M 10M to 70M d Throughput 4

5 WiMAX Applications 2 FRACTIONAL T1 for SMALL BUSINESS T1+ LEVEL SERVICE ENTERPRISE BACKHAUL for HOTSPOTS d 3 Mobile Backhaul d RESIDENTIAL & SoHo DSL LEVEL SERVICE 1 WMAN Nomadic Coverage --> handoff from HOT SPOTS H H H H H H H H H e 5 = wide area coverage outside of Hot Spots INTERNET BACKBONE BWA Operator Network Backbone Mobility Wireless Local Loop in Developing 6 Nations 5 Source: Alvarion

6 Comparing d/e with Others Channel Standard bits/sec/ FDD/TDD DL Peak UL Peak Bandwidth Body hz GPRS 160 kbps 160 kbps KHz FDD Edge 480 kbps 480 kbps 2.40 WCDMA FDD/TDD 2 Mbps 2 Mbps 3GPP HSDPA 5 MHz FDD 14.4 Mbps 7 Mbps G1X 640 kbps 450 kbps 0.51 EvDO 1.25 MHz FDD 3.1 Mbps 1.8 Mbps 3GPP 2.48 EvDv 3.1 Mbps 1.8 Mbps d/e upto 20 MHz FDD/TDD upto 75 Mbps upto 75 Mbps IEEE 3.75 Flarion 1.25 MHz FDD 3.2 Mbps 900 kbps Normalized Throughput Comparison (Peak Bursts) DL bits/sec/hz GPRS Edge WCDMA HSDPA 3G1X EvDO EvDv d/e Flarion 6

7 Specifications Network Mngmnt f: Management Information Blocks g: Mob. Mgmt. Plane Procedures and Services MAC PHY m Enhanced QoS/ Security/ Interworking with IMT2K/ Mobility/ BCast H/O/ Legacy Support Larger Cells (30 km) Peak rate 100 MBPS (M)/1GBPS (F), Interference Avoidance Reduced Latency, RRM, Coverage, ebcmc e Mobility Enhancements: Handoff/ ActiveSet/ Anchor-Target AAS. MiMo, STC S-OFDMA: 2048 / 1024 / 512 / a SCa OFDM 256 OFDMA b Wireless- HUMAN OFDM TDM FDD/TDD ATM +Packet CS c System Profiles for crossmanufacturer Conformance (802.16d) 2 to 6 GHz 2 to 6 GHz <11 GHz GHz NLOS NLOS NLOS LOS 100 MBPS 15 MBPS <75MBPS <134 MBPS Mobile 1.75 to 20 MHz Mobile 1.75 to 20 MHz Fixed Fixed 1.75 to 20 MHz 20/25/28 MHz 7

8 Why OFDM Rayleigh Envelope Variation is time and frequency NLOS signal envelopes are Rayleigh distributed The signal fades both with time and frequency separation Time correlation decreases with increasing velocity (Doppler) Frequency correlation decreases with increased multipath delay spread Diversity is the key to enhance performance in fading environments CDMA uses multiple rake fingers to capture frequency diversity OFDM uses parallel long duration pulses to capture time diversity Frequency diversity is captured by coding across time and frequency 8

9 OFDM Basics T G T Useful 1/T Useful Frequency f 4 f 3 f 2 f 1 f 0 DC Signal is accessible in time and frequency Time variations and frequency variations can be coded/interleaved across Advanced Space-Time-Frequency Coding Guard Interval absorbs the designed multipath effects Single tap multiplicative equalizer NLOS operation OFDMA: Single Frequency Network operation with reuse factor of 1 Planning benefit + Spectrum Utilization Invented at Bell Labs : Chang and Gibby, 1960s DVB-T, SDARs, WiFi, WiMax, HiperLAN/MAN, DAB, DSL and coming in EvDO, UMTS! R.W. Chang [1966], Synthesis of Band-Limited Orthogonal Signals for Multichannel Data Transmission, Bell System Technical Journal, 45, pp B. R. Salzberg [1967], Performance of an Efficient Parallel Data Transmission System, IEEE Transactions on Communication Technology, 15, 6, pp R.W. Chang, and R.A. Gibby [1968], Theoretical Study of Performance of an Orthogonal Multiplexing Data Transmission Scheme, IEEE Transactions on Communication Technology, 16, 4, pp S.B. Weinstein, and P.M. Ebert [1971], Data Transmission by Frequency-Division Multiplexing Using the Discrete Fourier Transform, IEEE Transactions on Communication Technology, 19, 5, pp Time Freq 9

10 OFDMA Operations N E Subcarriers Pilot Subchannel A Group 1 Group 2 Group N G 1 FFT Subchannel B Sub Channels SS A SS C Ranging Sub Channels SS B Preamble SS E SS D Time Different modulation/coding in each sub channel Media Access Protocol (MAP) messages are used to assign SSs to Sub channels FFT Size = 2048; DL: N G = 48 / N E = 32; UL: N G = 53 / N E = 32; 1 Schannel 1/32 nd of total BW Sub-carriers are assigned in a pseudorandom fashion to the SSs High throughput SSs are assigned more that one SC SSs need only modulate a few of the 2048 SCs/ BS modulates all Commensurate with low power CPEs and building penetration loss Throughput per Sub channel (6 MHz) = (QPSK) / (16 QAM) / (64 QAM) (kbps) Total Throughput (6 MHz) = 4.8 / 11.6 / 18.2 MBPS Wireless and Optical Communications Conference, Reference: NJIT, Koffman, April 27th Roman, 2007 Broadband Wireless Access Solutions Based on OFDM Access in IEEE , IEEE Comm. Magazine,April 2002, pp

11 802.16e and WiMax Profiles PhyProfiles Bandwidth Duplexing (OFDMA_R1 to OFDMA_R30 RF profiles) ofdma_profp MHz TDD ofdma_profp2 3.5 MHz TDD/FDD ofdma_profp3 7.0 MHz TDD/FDD ofdma_profp MHz TDD ofdma_profp5 14 MHz TDD/FDD ofdma_profp MHz TDD ofdma_profp7 28 MHz TDD/FDD ofdma_profp8 10 MHz TDD ofdma_profp9 20 Mhz TDD Modulation Symbol Rate 4/16/64. (BWMHz-0.88)/1.25 FFTSize: D: 2048 / E: 2048/1024/512/128 (SOFDMA) Frequency band (GHz) Channelization (MHz) FFT Size TDD TDD TDD TDD TDD TDD TDD TDD TDD TDD TDD TDD TDD TDD TDD 11

12 Spectrum Availability License Exempt Licensed UHF ISM UPCS WCS ISM MMDS Int l Int l Low/Mid UNII Upper UNII & ISM GHz UHF ISM UPCS WCS Channels 60-69, called the upper 700Mhz, are by congressional statute to be reclaimed for new services (broadband wireless). Industrial, Scientific & Medical Band License exempt band License exempt Personal Communications Services Wireless Communications Service. Licensed by Verizon, Bellsouth & AT&T ISM Industrial, Scientific & Medical Band License exempt band MMDS Int l Multi-channel Multipoint Distribution Service. Licensed in U.S. by Sprint, Worldcom & Nextel, Nucentrix. Licensed Bands- Europe, Latin America, Asia Licensed Bands-Japan UNII License exempt National Information Infrastructure band Source: Intel Corporation US Gov t Exclusive 12 Non-Gov t Exclusive

13 Mobile WiMax System Architecture FE/GigE Service Core OMS ISP Backhaul & Aggregation Access Service Node Core IP Network HA MGW PSTN MRFP BGCF MGCF AAA DNS DHCP MRFC CSCF IMS Ranging Basic Capability Setup Registration Establish IP Connectivity Mobility (MIP, P-MIP, SIP) QoS Subscriber Access Management Authenticate, Authorize, Account SLA enforcement Handover Management Allocate IP addresses (SIP) Proxy Mobile IP or FA Call Control Gateway Functionalities IP address allocation (MIP) 13

14 Mobile IP in Mobile WiMax R1 ASN R3 CSN IP IP CS CS DP Fn L2 DP Fn L2 MIP L2 MIP L e e MS MIP Client BS FA HA HoA@ payload BS@+Tunnel id HoA@ payload CoA@ HoA@ payload HoA@ payload Intra-ASN Data Path MIP tunnel CS: Convergence Sublayer DP: Data path function Source: WiMax Forum NWG 14

15 WiMAX Handoffs (1) ASN Anchored Mobility (Micro Mobility) Mobility of an MS not involving a CoA update (i.e. a MIP re-registration) with the following functions defined Data Path (Bearer) Function: Manages the data path setup and includes procedures for data packet transmission between two functional entities (usually b/w BSs) Type 1: IP or Eth forwarding over IETF L2 (Eth or MPLS) or L3 IP-in-IP or GRE...) transport Type 2: E MAC forwarding over IETF L2 (Eth or MPLS) or L3 IP-in-IP or GRE...) transport Handoff Function: Controls overall HO decision operation and signaling procedures related to HO Context Function: Addresses the exchanges required in order to setup any state or retrieve any state in network elements. Example of Layer-2 Anchored Type 2 DP Function L3 IP Data Path IP Cloud Type 2 DP carrying L2 packets Anchor Data Path Function L2 Session Anchoring L2 Data Anchoring Packet Buffering Serving Data Path Function Air Interface to MS MAC PDU generation Scheduling Target Data Path Function Network Re-entry processing Update of Air Interface MS MS MS 15

16 WiMAX Handoffs (2) CSN Anchored Mobility (Macro Mobility) Mobile IP based macro mobility between the ASN and CSN across R3 reference point In case of IPv4 implies re-anchoring of FAs If FA serves multiple BSs then CSN anchored mobility umbrellas ASN anchored mobility (within the FA) Reverse Tunneling b/w ASN and CSN shall be supported For non-roaming HA must be in CSN, Roaming: HA either in V-NSP or H-NSP User subscription profile in H-CSN MIP client shall always operate as if in a foreign network P-MIP shall be supported in which case MS is unaware of CSN anchored mobility R3 Mobility Scope NAP 1 MS BS BS BS NAP ASN Network ASN Network FA FA FA NSP HA MS BS BS BS BS ASN Network ASN Network FA FA NSP HA NAP 2 NAP: Network Access Provider NSP: Network Service Provider 16

17 802.16e QoS Offerings QoS Class Type of traffic Scheduling Parameters Unsolicited Grant Service (UGS) Reatlime data services with fixed size data and period transmissions. E.g: T1/E1/VoIP w/o silence suppression BS grants service periodically. SS contention and piggyback requests prohibited. Unsloicited grant size, Grants per interval, Nominal grant interval, Tolerated grant jitter Realtime Polling Services (rtps) Enhanced RTPS (ertps) Real time data with variable sized packets and with periodic transmission. E.g: MPEG Real-time services with variable size data packets on a periodic basis, such as Voice over IP services with silence suppression. Periodic unicast request opportunities granted to SS. Contention/piggyback requests prohibited Efficiency of both UGS and rtps. Unicast grants in an unsolicited manner like in UGS, UGS allocations are fixed in size, ertps allocations are dynamic. Piggyback. Nominal polling interval, tolerated poll jitter, minimum reserved traffic rate Maximum Sustained Traffic Rate, the Minimum Reserved Traffic Rate, the Maximum Latency, and the Request/Transmission Policy. Non-realtime polling services (nrtps) Best Effort (BE) Parameters for QoS Provisioning Delay tolerant with variable packet size and aperiodic transmission. E.g.: FTP Handled on a space available basis Service Flow Identifier Connection ID Service Class Name QoS Parameter Set Type Traffic Priority Maximum Sustained Traffic Rate Maximum Traffic Burst Periodic unicast request opportunities granted to SS but farther apart. Contention/piggyback requests allowed Contention/piggyback requests from SS to BS Nominal polling interval, minimum reserved traffic rate, traffic priority Minimum reserved traffic rate, traffic priority Minimum Reserved Traffic Rate Minimum Tolerable Traffic Rate Service Flow Scheduling Type Request/Transmission Policy Tolerated Jitter Maximum Latency Fixed-length versus Variable-length SDU Indicator QoS parameters are of 3 types: {Provisioned, admitted and active} == QoS Parameter Set 17

18 Summary Mobile WiMax is a forerunner to the 4G evolution and architecturally is well ahead of LTE and EvDO Rev C OFDM and the all IP architecture is what 4G systems are heading towards and WiMax is already there (and will converge with 16m) Mobile WiMax offers a scalable solution that accommodates users with varying capacity demands Mobile WiMax has superior QoS mechanisms built into the standards Mobile WiMax offers a a mobility evolution plan (SIP, P-MIP, MIP; IPv4, IPv6) Drawbacks: WiMax has defined only TDD operations (government sector...) Large bandwidths require large spectrum to tessellate (MiMo, AAS will alleviate) Higher band of operation will shorten coverage (need to work on lower carriers...) 18

19 Appendix 19

20 So What is LoS? Tx Rx 3 rd Fresnel Zone 2 nd Fresnel Zone r 1 1 st Fresnel Zone c 1 N λ d F N = d + 1 d d Tx Rx Set N = 1, d 1, d 2 r 1 d 1 d2 c r 1 : LOS c 1 < 0.6 r 1 : NLOS 20

21 System Operation SS enters BS service area SS SS Scans for DL Channel DL Synched Obtain UL Parameters Ranging and Adjust Parameters Negotiate Basic Capabilities Register with BS Establish IP Connectivity Establish ToD Transfer Operational Parameters DL-MAP Broadcast: Phy Synch field, Operator ID, Sector ID, MAP message length, DCD broadcast: BS Power, PHY type, DL burst profile, Modulation type, FEC, Phy synch, BSID + UCD broadcast: PHY sycnh field, BSID, Phy specs, Range-Req: requested DL burst profile, SS MAC addr, Ranging anomalies, SS broadcast capabilities Range-Rsp: Timing adjust, Pwr lvl adjust, Freq offset adj, ranging status, DL freq override, UL freq override, burst profile, SS Mac addr, CID,... SS Bc-Req: CID, PHY params supported, Bandwidth allocations supported, SS Bc-Rsp: CID, PHY params supported, Bandwidth allocations supported, Reg-Req: CID, Hashed Msg Auth Code, IP vers, Vendor ID, CS capability, ARQ params Reg-Rsp: CID, Ok/Not, HMAC tuple, IP vers, Vendor ID, CS capability, ARQ params DHCP-Req: H/W type = Ethernet, MAC addr., Params requested: Subnet mask, Time offset, Router option, Time server option, Vendor class identifier DHCP-Req: IP Addr., TFTP provisioning server name, Time offset, List of routers, ToD Req/Rsp TFTP Config File(Download SS binary Configuration File) TFTP Complete: CID TFTP RSP: CID, OK/Not BS Establish Provisioned Connections DSA-Req (SS or BS initiated): Service flow params, CS parameter encodings(802.3, 802.1p, 1q, ATM..), DSA-Rsp): CID, Trnsaction ID, Conirmation Code, Service flow params, CS param encodings, Service flow error set, DSA: Dynamic Service Allocation Operational 21

22 WiBro: 2.3 GHz Portable Internet Standardization and Commercialization: Korean standardization effort TTA Named in April 2004: Wireless Broadband WiBro Urban, High data rate >1 <60 km/hr Draft Completion/802.16e Harmonization: Q205, Field testing : 4Q05, Commercialization: 1Q06 Korea Information Strategy Development Institute: >10.5M users by 2010 System Profile Standard activities: Radio (PHY, MAC, RRC), Services & Network, IPR Processing, I natl coordination System Definition: Frequency Reuse: GHz only TDD-only with 5 m-sec framing Service Coverage: 1 km Mobility < 60 km/hr, Spectral Efficiency: DL/UL = 6/2 (max) 2/1 (avg) Throughput/user: DL/UL = 3/1 Mbps (max); 512/128 kbps (avg) Throughput/sector: DL/UL = 18/6 MBPS QPSK/16/64 QAM Handoff time: 150 ms 10 MHz B/W OFDMA Network elements: PSS (Personal SS), RAS (Radio Access Station), ACR (Access Control Router) ACR: Packet classification, header suppression, service flow management, traffic switching and integration, H/O management... Source: ITU-APT Regional Seminar 2004 PSS RAS ACR Core PSS RAS 22