mm Wave Communications J Klutto Milleth CEWiT

Transcription

1 mm Wave Communications J Klutto Milleth CEWiT

2 Technology Options for Future Identification of new spectrum LTE extendable up to 60 GHz mm Wave Communications Handling large bandwidths Full duplexing on the same channel Feasibility, Tx Rx isolation Capacity increase using MIMO Massive MIMO or Full Dimension MIMO or Large MIMO Multiple RATs complementing each other Both 3GPP and non-3gpp with WiFi and LTE playing a major role Mesh of inter connections D2D, P2M, M2P, and M2M leading to more frequency reuse A completely new air interface Leveraging existing investments Cost involved in adopting new technology in current bands

3 mm Wave Motivation Rapid increase in the usage of mobile data Main challenge for wireless service providers Delivery of high quality, low latency video & multi media contents Limited availability of spectrum between 700MHz to 3GHz Efficient management of spectrum to meet current demand More bandwidth needed to meet future demand Enormous spectrum available in millimeter wave band Millimeter waves is expected to be one of the future option Radio Frequencies GHz are Millimeter Waves. Wavelengths in the range of 1-10mm Typical applications of millimeter Wave are Point-to-point communication o Inter satellite links, cellular backhaul Point-to-multipoint communication

4 Why 60 GHz band? Requirement of data rate expected 1000 x Huge amount of spectrum available globally Worldwide harmonization is possible Spectrum availability around 60 GHz Unlike UWB spectrum is available worldwide Recent advances in 60 GHz front end technologies Gallium Arsenide expensive chipsets Silicon and Germanium less expensive CMOS cheaper

5 Propagation effects Less penetration and more propagation loss Sensitive to shadowing o NLoS with tremendous attenuation Atmospheric attenuation & rain absorption Foliage Loss Low diffraction and diffusion (less specular) Less coverage means more reuse Src: Rapoport et al Src: Communication Magazine

6 Massive MIMO Vs mm Wave MIMO Massive MIMO Limited spectrum availability in the cellular bands Large number of BS antennas Large number of users served simultaneously MU-MIMO on same resource mm Wave MIMO Huge amount of spectrum available at 60 GHz Requires large antenna arrays Smaller wave length makes this possible Array gain from larger arrays

7 mm Wave Advantages Smaller wave length Smaller size of RF components including antennas o More antennas packed in a small area o More antenna gain and directional Array gain compensates for path loss to a certain extent Better SINR Focussed beam to users resulting in reduced interference Improved spectral efficiency Reduced power amplifier cost Multiple low power amplifiers to transmit with reduced power No rich multi-path Effect of thermal noise and fading is minimized

8 mm Wave Challenges Sensitive to misaligned beams Less penetration power More number of RF chains Limited to LoS Very small cells Mobility a challenge Feedback overhead is very high Channel reciprocity in TDD system helps Uplink interference contaminates pilots Link Acquisition: A user and a BS may need to scan lots of angular positions where a narrow beam could possibly be found Deploy extremely large coding gains over a wider beam that is successively narrowed in a multistage acquisition procedure

9 SINR Comparison Cellular Network Mm Wave Network

10 Mm Wave Beamforming Digital beamforming Provides higher degree of freedom and better performance More complexity and cost due to the separate FFT/IFFT blocks (for OFDM systems), DACs, and ADCs per RF chain Analog beamforming Simple method of generating high beamforming gains from large number of antennas Less flexible than digital beamforming Hybrid beamforming The sharp beams formed with analog beamforming compensate for the large path loss at mmwave bands Digital beamforming provides the necessary flexibility to perform advanced multi-antenna techniques such as multi-beam MIMO

11 mm Wave Spectrum in US FCC regulations Frequency Band (GHz) Label Licensed Specific Purpose Maximum Transmit Power Minimum Antenna Gain V band No Point to Point or multipoint communication 27dBm N/A 71-76,81-86 & excluding E band Yes Point to point Communication 35dBm 43dBi W band No Indoor applications - N/A

12 E-band Channelization Elsewhere Src: Communication Magazine E-band channelization in: a) the United States and Canada; b) the United Kingdom and Australia; c) Europe.

13 E-band FCC opened up E band for exclusive federal government use in US ETSI released technical rules for equipments operating in E-band (similar proposals in United Kingdom and Australia) Allocations for fixed services were first established by the ITU at the 1979 WARC-79 World Radio Communication Conference light licensing scheme introduced in US (Canada adopted the same) Plan for India?

14 Questions?