A Simplified Simultaneous Transmit and Receive Mechanism

1. A Simplified Simultaneous Transmit and Receive Mechanism Authors: Date: 2014-03-17 Raja Banerjea, CSR

2. Abstract Raja Banerjea, CSR In band STR (Full Duplex) transmission allows 100% increase in Network throughput. Traditional STR transmission require STR AP and STR capable STA. We present a simplified STR mechanism which only requires STR capability at the AP and can be supported by traditional STAs.

3. Topics Raja Banerjea, CSR • Increasing Network Throughput • In Band STR Challenges • A simplified STR mechanism • Analytic results showing STR performance • Next Steps

4. Increasing Network Throughput • Max Data Rate based on Shannon Limit = B log 2 (1 + S/N) x (1- T GI / T SYML )x N data / N carr • A 5 dB RF Noise Figure + Implementation noise is considered for both the 802.11 sensitivity and the theoretical maximum. Conclusion: Modulations above 16-QAM ¾ are already spectrally efficient STR allows 100 % increase in network throughput. These gains are difficult to achieve otherwise. Raja Banerjea, CSR

5. In Band STR Challenges • IEEE 11-13/1122r0 “Considerations for In-Band Simultaneous Transmit and Receive (STR) feature in HEW” presented state of STR technology. Total Cancellation of 110 dB is achievable • However the system cost is considerable • RF Isolation • Analog Cancellation • Digital Cancellation • The proposed mechanism enables In Band STR communication using In Band STR capable AP and legacy STAs Raja Banerjea, CSR

6. Proposed STR in WLAN • Leverage attenuation and path loss between STAs to develop a simplified STR solution. The increased complexity is only at the Access Point. • Access Point uses knowledge of path loss between STAs to Group STAs for In band STR transmission. Traditional WLAN: Half Duplex transmission In Band STR Proposed Solution Naveen Kakani, CSR

7. Benefits of simplified In Band STR • 100 % increase in network throughput • No increase in complexity at the STA • Compatible with legacy deployments • Takes advantage of Wall attenuation and Path Loss Raja Banerjea, CSR

8. Analytical Results • Considered Path Loss between AP and STAs in some typical deployment scenarios • IEEE 802.11n channel model • L(d) = LFS(d BP) + 35 log10(d / d BP) d > d BP • LFS(d BP) = 40 dB (2.4 GHz) ; 46 dB (5 GHz) • d BP = 1 m • Wall Loss = 12 dB • Typical Scenarios • Small Residence ( ~ 1200 sq ft ) • Ranch House ( ~ 3000 sq ft ) • Class Rooms Raja Banerjea, CSR

9. Analytical Results • AP and STA-1 location was fixed and the path loss measured between AP and STA1 (PL AP_STA-1) and the location and STA-1 ( PL STA-1STA-2) • Path Loss is measured using the shortest path to estimate distance and number of walls • If measured difference in Path Loss is greater than TBD dB then In Band STR is feasible in that configuration Raja Banerjea, CSR

10. Ranch House ( ~ 3000 sq ft ) Fixed AP STA2 PL AP_STA1 PL STA1_STA2 Fixed STA1 Raja Banerjea, CSR

11. Small Residence ( ~ 1200 sq ft ) Raja Banerjea, CSR

12. Ranch House ( ~ 3000 sq ft ) Raja Banerjea, CSR

13. Class Rooms Raja Banerjea, CSR

14. Conclusion • In band STR can increase the network throughput by 100 % • The simplified In band STR mechanism leverages wall attenuation and path loss between STAs and enables STR where only the Access Point is STR capable. • In Band STR can be used along with MU-MIMO and SU-MIMO and provides increased throughput Raja Banerjea, CSR

15. Next Steps • Path Loss Measurements in typical environments • Measure the allowed co-channel interference • A simplified MAC protocol for In-Band STR Raja Banerjea, CSR

16. References Raja Banerjea, CSR [1]11-13-1421-01-hew-str-radios-and-str-media-access.pptx [2] 11-13-0765-02-0hew-co-time-co-frequency-full-duplex-for-802.11-wlan.pptx [3] 11-13-1122r0-considerations for In-Band Simultaneous Transmit and Receive (STR) feature in HEW