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802.11 WNG Presentation: 6-10 GHz extensions to 802.11, Part 3. Date: 2012-03-13. Authors:. Abstract.
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802.11 WNG Presentation: 6-10 GHz extensions to 802.11, Part 3 Date: 2012-03-13 Authors:
Abstract This document presents the possibility of using existing shared spectrum allocation in 6-10.5GHz as an extension frequency band for an 802.11ac PHY with a 500MHz bandwidth. It is a follow up to document 12/0096r0, 11/743r0, and 11/385r1 https://mentor.ieee.org/802.11/dcn/12/11-12-0096-00-0wng-6-10ghz-extensions-to-802-11ac-part2.ppt https://mentor.ieee.org/802.11/dcn/11/11-11-0743-00-0wng-6-9ghz-extensions-to-802-11.ppt https://mentor.ieee.org/802.11/dcn/11/11-11-0385-01-0wng-ultrwideband-spectrum-for-802-11.ppt
What’s New in This Presentation? • >1Gbps PHY rates • Link budgets • PHY issues • Eb/No requirements • ADC/DAC requirements • EVM requirements • Use cases and spatial capacity • How this proposal complements 802.11ac
Why a frequency extension for 802.11ac? • Gives needed capacity for high rate communications • Wireless docking/monitors using 802.11ac will tax existing 5GHz spectrum allocation • Some countries highly restrict 5GHz spectrum (China) • High density environments (cubicle farms) will have serious spatial capacity problems…interference, frequency reuse, etc. • Could leverage existing 802.11ac/ad MAC and PHY extensions • MU-MIMO, STBC, and other extensions will greatly enhance link budget…more than doubling range of SISO • Relatively “low hanging fruit” for existing 5GHz radios • Band starts at 6GHz – just above 5GHz ISM band • Extension of 5GHz bands – minimal antenna and RF impact • High bandwidth allows precision ranging/location • For applications that need relatively short range (<10 meters) and very high spatial capacity, this spectrum could be ideal
6-10GHz gives superb capacity for cube farms 2.5 m • At 320Mb/s, radius of coverage is ~3 meters (7.5GHz, SISO, CM2) • 960Mbps will give about 1.5 meters range (SISO, CM2) • In a cubicle, each user could have a dedicated channel • No beamforming assumed • Negligible interference between users • Specific results will depend on Eb/No, frequency, etc. • Small cells yield highest spatial capacity in users per square meter • 6-10GHz has a coverage area just larger than an average cubicle • With 7 channels available, channel reuse can be optimized for maximum capacity with minimum interference
Other Comments • Existing 802.11ac/ad PHY + MAC provides most of the hooks • 450/500MHz minimum bandwidth will require new MCS combinations • Effectiveness of beamforming is TBD • MIMO/MU-MIMO could be very useful • Can use simpler OFDM modulation (e.g. 16-QAM) • Lower EVM, less hardware complexity (but higher sampling rates) • At least five 500MHz channels are available in 6-9GHz • Up to 8 in some countries • Allows k=4 frequency reuse for high user density • Studies may be required to see how well MU-MIMO will operate • Other regulatory domains may permit <500MHz BW • Power consumption will be attractive • SISO: Estimate <400mW for 1Gbps in 40nm • 2x2 MIMO: Estimate <500mW for 1Gbps in 40nm
Background Work on Channel Models • Much work has been done on propagation models • http://grouper.ieee.org/groups/802/15/pub/2002/Nov02/02368r4P802-15_SG3a-Channel-Modeling-Subcommittee-Report.ZIP )
Example link budget • Based on 802.15.3a model with 528MHz BW • 8% PER for 960 Mbps is at about 1.5 meters with 7.1 dB margin
PHY Issues • Shannon capacity is linear with bandwidth • In 11ac, multiple tradeoffs over bandwidth, number of spatial streams, modulation order • For >500MHz channels, can use SISO, MRC, simple (2x2) MIMO, and lower order modulation • Selective fading channel with multiple fades (MRC works well) • Eb/No requirements are much lower than narrowband systems • For 960 Mbps at 1.5 meters: • SISO • ADC/DAC resolution required: 6 bits • EVM ≈ -21.5 dB • assumes modified dual carrier modulation, LDPC • Change in MDCM demapper can yield >2Gbps PHY • Adding maximum ratio combining improves range or robustness • 2x2 MIMO gives 3-6dB link budget improvement
Spatial Capacity • Wireless dock and sync need very high spatial capacity • Cubicle density in enterprise is worst case • Wi-Fi Display will need multiple HD video grade streams • Dedicated channels desired for enhanced QoS, lower interference • 6-10 GHz offers very high capacity with low complexity • 6-10GHz systems can have a minimum of 5 channels globally, up to 8 in US • Each system can operate in adjacent frequency channels • 5 channels x 1 Gbps/channel / 2.25 sq meters = 2.2 Gbps/sec/m2 • MRC or MIMO will increase coverage area and/or data rate • SISO would be ideal for mobile, handheld platforms • Very high spatial capacity without multiple antennas/spatial streams • Fewer antennas, fewer RF and ADC/DAC chains
Summary • Additional spectrum will be needed for wireless docking and sync • 6-10 GHz offers a minimum of 5 channels, each of which can have 1Gbps or more in a cubicle usage model • Spectrum regulations are in place worldwide • >2Gbps/m2 spatial capacity • Design of a 6-10 GHz RF is a relatively easy extension to existing 802.11ac • Band begins just above 5.7GHz ISM band • Antennas exist that cover 5-10 GHz, allowing “11ac+” • Can use SISO, MRC or “easy” MIMO (2x2, 16-QAM) • Most capacity improvement comes from B term in Shannon • Some new MCS will need to be added to 11ac • Much work has already been done on channel models, regulations, link budgets