802.11 WNG Presentation: 6-9GHz extensions to 802.11, Part 2 July 2007 Nov 2009 January 2012 802.11 WNG Presentation: 6-9GHz extensions to 802.11, Part 2 Date: 2012-01-17 Authors: Peter Ecclesine (Cisco Systems)

Nov 2009 January 2012 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 11/743r0 (and 11/385r1)

January 2012 Background The US FCC announced spectrum availability of 3-10.5GHz for ultrawideband in February, 2002 “Spectral underlay” – operates without any spectrum etiquette or spectrum sensing PSD limit: -41.3dBm/MHz ≈ -14dBm in a 500MHz BW 500MHz (or 20% fractional bandwidth) minimum Most other countries have now finalized regulations UK, EU, Korea, China, Canada, Japan Operation from 5-6GHz generally not allowed Many restrictions in 3-5GHz, including spectrum sensing (DAA) Some countries have expressed an interest in allowing higher Tx power Some IEEE efforts have addressed this spectrum 802.15.3a – withdrew PAR in January 2006 802.15.4a – Approved in March 2007, but minimal market deployment Spectrum is underutilized and globally available

Wider BW: Shannon Capacity (SISO) January 2012 Wider BW: Shannon Capacity (SISO) Courtesy Prof. Jeff Reed, Va Tech) Wide bandwidths can have high capacity at low SNR Small cells increase spatial capacity Can achieve MIMO speeds of narrowband with SISO simplicity Using MIMO can achieve even higher capacity

Worldwide Regulations Nov 2009 January 2012 Worldwide Regulations US Feb-02 EU Dec-06 2010 w/DAA 2010 w/DAA See Note 2010 w/DAA Japan Sep-2006 2010 w/DAA 2010 w/DAA Korea Sep-2006 2010 w/DAA 2010 w/DAA 2010 w/DAA Canada March-2009 China Jan-09 2010 w/DAA 3.168 GHz 4.752 6.336 7.392 7.920 8.976 9.504 10.560 3GHz of contiguous bandwidth from 6-9GHz is available Japan & Korea don’t allow operation from 6-7.15/7.25GHz EU has a detection requirement in 8.5-9GHz similar to 5.4GHz Minimum bandwidth is 450 or 500MHz Five or more channels available globally Peter Ecclesine (Cisco Systems)

Why a frequency extension for 802.11ac? January 2012 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

6-10 GHz offers excellent spatial capacity January 2012 6-10 GHz offers excellent spatial capacity 5 7 4 1 6 3 2 Same channel is reused ~11 meters away…>20dB of extra path loss Capacity is maximized by assuming hexagonal pattern Same channel can be reused in device 11 meters away with negligible interference (>14dB signal-to-interference ratio) – perfect for cube farms Closed loop power control will improve this capacity ≈22 meters

Three channels are not adequate for cubicles Jan 2012 Three channels are not adequate for cubicles 1 2 3 3 4 2 1 1 2 3 4 Another view of four channel reuse in a cubicle layout Three channel reuse can’t work with rectangular cubicles Four channels CAN work In theory, three channels can be made to work, BUT… In a cube farm, 4 channels are required, since the cubicles are joined at the corners…and the cluster may not always be in the same location in the cube (4 color map problem)

6-10GHz gives superb capacity for cube farms Jan 2012 6-10GHz gives superb capacity for cube farms 2.5 m At 320Mb/s, radius of coverage is ~3 meters (7.5GHz, 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

January 2012 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) Shannon capacity of 500MHz channel is very high at low SNR At least five 500MHz channels are available in 6-9GHz 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 January 2012 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 ) Target Channel Characteristics RMS delay Notes CM1 5.28nsec LOS(0~4m) CM2 8.03nsec NLOS(0~4m) CM3 14.28nsec NLOS(4~10m) CM4 25nsec 25nsec RMS delay spread to represent an extreme multi-path channel

Example link budget Based on 802.15.3a model with 528MHz BW January 2012 Example link budget Parameter Value Information Data Rate 106.7 Mb/s 200 Mb/s 480 Mb/s Average TX Power -10.3 dBm Total Path Loss 64.2 dB (@ 10 meters) 56.2 dB (@ 4 meters) 50.2 dB (@ 2 meters) Average RX Power -74.5 dBm -66.5 dBm -60.5 dBm Noise Power Per Bit -93.7 dBm -91.0 dBm -87.2 dBm CMOS RX Noise Figure 6.6 dB Total Noise Power -87.1 dBm -84.4 dBm -80.6 dBm Required Eb/N0 3.8 dB 4.4 dB 4.7 dB Implementation Loss 2.5 dB Link Margin 6.3 dB 11.0 dB 12.9 dB RX Sensitivity Level -80.8 dBm -77.5 dBm -73.4 dB Based on 802.15.3a model with 528MHz BW

January 2012 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 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 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