In-band Full Duplex Radios and System Performance

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1 January 25 In-band Full Duplex Radios and System Performance Date: doc.: IEEE ax Authors: Name Affiliations Address Phone Kapseok Chang 28 Gajeong-ro, Yuseonggu, Daejeon 35-7, Korea Hyungsik Ju " Seon-Ae Kim " Byung-Jae Kwak " Moon-Sik Lee " Jimin Bae KAIST 29 Daehak-ro, Yuseong-gu, Daejeon , Korea Eunhye Park KAIST " Youngnam Han KAIST " Woojin Ahn Yonsei University Ronny Yongho Kim Korea National University of Transportation Slide

2 January 25 Outline doc.: IEEE ax Feasibility of In-band Full Duplex (IFD) Concept Merit Demerit Classification of self-interference cancellation (SIC) Technology State of the art in SIC System Performance Introduction Duplex mode 3-node form IFD Pairwise IFD Residential scenario System-level simulation environment Evaluation result Outdoor large BSS scenario System-level simulation environment Evaluation result Summary Slide 2

3 January 25 doc.: IEEE ax Feasibility of In-band Full Duplex (IFD) Slide 3

4 January 25 doc.: IEEE ax What are current wireless radios? Frequency Division Duplexing (FDD) In other words, Out-band Full Duplex (OFD) Time Division Duplexing () In other words, In-band Half Duplex (IHD) Frequency Frequency Rx Tx Frequency Frequency 2 Tx Rx Tx/Rx Timeslot Timeslot 2 Tx/Rx FDD Time Time Problem There is no full resource utilization. FDD wastes frequency resource, i.e. Frequency 2. wastes time resource, i.e. Timeslot 2. What is one of solutions to resolve the problem? That is In-band Full Duplex (IFD). 4

5 January 25 Concept of IFD doc.: IEEE ax IFD radio can simultaneously transmit and receive on the same frequency channel Tx/Rx Frequency Timeslot / Frequency Tx/Rx Time IFD does not waste frequency and time resources, i.e. Frequency 2 and Timeslot 2. 5

January 25 Merit: Spectral Efficiency doc.: IEEE 82.

6 January 25 Merit: Spectral Efficiency doc.: IEEE ax Basic operating scenario of bi-directional IFD communications with single antenna Theoretical Ergodic capacities of ideal IFD and OFD/IHD ( ) ( ) C IFD = C ab + Cba C OFD/IHD = C ( ) 2 ab + C ( ) ( ) 2 ba, where Cxy = log2 The link capacity of IFD is double than that of OFD/IHD. ( ) + SNR xy 6

7 January 25 doc.: IEEE ax Demerit: Self-Interference Basic transceiver structure Self-interference (i.e. self transmitted signal) is generated as below. Tx Base Band DAC PA Antenna Self- Interference Signal Rx Base Band ADC LNA Desired received signal Very strong self-interference signal [] ~db stronger than desired received signal strength for IEEE 82. Wi-Fi and LTE-A Small Cell 7

8 January 25 doc.: IEEE ax Demerit: Co-Channel Interference Operating scenario of IFD capable AP supporting IHD capable user nodes [2][3] It can be a priority for AP only to have IFD capability in terms of power supplying and backward compatibility. Primary link Secondary link Co-channel Interference (CCI) Co-channel interference (CCI) occurs. Requires further information (e.g. CCI) to setup the secondary link 8

9 January 25 doc.: IEEE ax Classification of Self-Interference Cancellation (SIC) Technology Propagation SIC in antenna domain Analog SIC in circuit domain DAC ADC Digital SIC in baseband domain Encoder Decoder 9

10 January 25 Key Issues on SIC doc.: IEEE ax Inefficiency of propagation SIC (PSIC) Mainly using physical isolation between Tx and Rx antennas [4] Any propagation SIC technologies are not recommended because the merit of IFD in terms of spectral efficiency over OFD/IHD disappears The form-factor size of IFD transceiver becomes larger. Thus, single antenna is recommended to realize the merit of spectral efficiency That is to say, no propagation SIC gain in antenna domain Importance of analog SIC (ASIC) Protecting analog-to-digital converter (ADC) saturation Analog SIC technology is the crux of IFD commercialization. Non-linear component in digital SIC (DSIC) Dependent on surrounding environment of IFD transceiver, non-linear component self-interference signal cannot be sufficiently cancelled in analog domain. In this case, there is no successful decoding without this component cancellation.

11 January 25 State of the art in SIC [2] doc.: IEEE ax Slide

12 January 25 doc.: IEEE ax State-of-the-art SIC Performance Comparison Institute Year (Standard) Freq. (GHz) BW (MHz) PSIC ASIC DSIC Total SIC NEC (Japan) dB none 2dB 75dB Rice University (US) Stanford University Kumu networks [] (US) dB 24dB none 8dB dB 2dB 85dB dB 24dB 95dB dB 25dB 5dB 7dB dB 28dB 73dB none 6dB 5dB db DUPLO [6] none 5dB RF Window (Korea) WITHUS (Korea) LTE WCDMA LTE WCDMA 2 2 6dB none db 7dB 2 35dB none 35dB 7dB AirPoint (Korea) LTE dB none 35dB 9dB SOLiD (Korea) 2 65dB none 35dB db

13 January 25 View and Result on SIC doc.: IEEE ax Propagation SIC No need to achieve double spectral efficiency, that is, single shared antenna Analog SIC Supporting wide bandwidth e.g. MHz Achieving at least stable 8dB SIC to reduce quantization error in digital domain RF analog FIR filter is needed Digital SIC Designing residual nonlinear component SIC as well as linear-component SIC for successful decoding Result based on S/W simulator Condition Single antenna, Circulator/Antenna channel modelling, Low Pass Filter modelling, nonlinear amplifier modelling No consideration in other hardware impairments We see more than db SIC with our SIC technologies. See the right figure. Average Uncoded BER MCS Case:., fading:off, AWGN:ON, Over-sampling freq:8. MHz Theoretic BER: AWGN Received desired Es/N [db]

14 January 25 doc.: IEEE ax System Performance and Summary Slide 4

15 January 25 doc.: IEEE ax Introduction IFD with single antenna is coming Feasibility of IFD communication now proved [] Dream of simultaneous transmission and reception (STR) coming true!! When IFD is employed in wireless communication networks, Up to 2x spectral efficiency Advanced MAC protocols to resolve various problems in half duplex (HD) counterparts vs. Self-Interference Increased co-channel interference (CCI) by STR Performance IFD-based wireless communication networks by system level simulation (SLS) Slide 5

16 January 25 Duplex Mode doc.: IEEE ax DL mode UL mode AP STA2 AP STA2 STA STA4 STA STA4 STA3 : Desired Signal : Co-Channel Interference (CCI) AP2 STA3 : Desired Signal : Co-Channel Interference (CCI) AP2 Slide 6

17 January 25 doc.: IEEE ax Duplex Mode 3 Node Form IFD (3n-IFD) [2][3] DL mode UL mode AP STA2 AP STA2 STA STA4 STA STA4 STA3 AP2 STA3 : Self-Interference : Self-Interference AP2 : Desired Signal : Co-Channel Interference (CCI) : Desired Signal : Co-Channel Interference (CCI) AP2 Slide 7

18 January 25 Duplex Mode Pairwise IFD [2][3] doc.: IEEE ax DL mode UL mode AP STA2 AP STA2 STA STA4 STA STA4 STA3 AP2 STA3 AP2 : Self-Interference : Self-Interference AP2 : Desired Signal : Co-Channel Interference (CCI) : Desired Signal : Co-Channel Interference (CCI) Slide 8

19 January 25 doc.: IEEE ax SLS Environment [5] Residential Scenario Residential building layout 5 floors, 3m height / floor 2 apartments / floor Apartment size : m m 3m Parameter APs in the building ( AP / room) 2 STAs / room Carrier frequency : 2.4GHz Bandwidth : 2MHz Noise Figure : 7dB mode AP: 2 Tx and 2 Rx antennas STA: Tx and Rx antennas IFD mode AP: 2 shared antennas STA: shared antenna Slide 9

20 m m January 25 doc.: IEEE ax Residential Scenario m SLS Environment (Contd.) General P-IFD mode AP : random deployment in room (uniform) STA : random deployment in room (uniform) Space-Scheduled (SSC) P-IFD & 3n-IFD mode AP : random deployment in room (uniform) STA Random deployment in room (uniform) minimum distance between STAs is 2m minimum distance between AP and STA is x m m Slide 2

21 January 25 Residential Scenario doc.: IEEE ax Evaluation Result () Effect of CCI Downlink SINR Signal power 2dBm -42dB 3dB SIC = CCI only.5.4 No need to reduce SI level.3 much below.2cci level. P-IFD, general(2db) P-IFD, general(8db) P-IFD, general(7db) P-IFD, general(5db) P-IFD, SSC(2dB) P-IFD, SSC(8dB) P-IFD, SSC(7dB) P-IFD, SSC(5dB) SINR UPlink SINR Noise level -9dBm It means in this CCI level, the achievable throughput with 8dB SIC case is close to that with perfect SIC case. Slide P-IFD, general(2db).4 P-IFD, general(8db) P-IFD, general(7db).3 P-IFD, general(5db).2 P-IFD, SSC(2dB) P-IFD, SSC(8dB). P-IFD, SSC(7dB) P-IFD, SSC(5dB) SINR

22 January 25 Residential Scenario doc.: IEEE ax Evaluation Result (2) Throughput DL Throughput UL Throughput P-IFD, general (2dB) P-IFD, general (7dB) 3n-IFD (2dB) P-IFD, SSC (2dB) P-IFD, SSC (7dB) Throughput (bps) x 7 Max. throughput of IFD 2 x max. throughput of. SSC is effective to enhance throughput of IFD P-IFD, general (2dB) P-IFD, general (7dB) 3n-IFD(2dB). P-IFD, SSC (2dB) P-IFD, SSC (7dB) Throughput (bps) x 7 Slide 22

23 January 25 Evaluation Result (3) Areal throughput (bps) Areal Throughput 6 x DL Areal Throughput P-IFD, general (2dB) P-IFD, general (8dB) P-IFD, general (7dB) P-IFD, general (5dB) P-IFD, SSC (2dB) P-IFD, SSC (8dB) P-IFD, SSC (7dB) P-IFD, SSC (5dB) 3n-IFD (2dB) Residential Scenario Areal throughput (bps) x UL Areal Throughput P-IFD, general (2dB) P-IFD, general (8dB) P-IFD, general (7dB) P-IFD, general (5dB) P-IFD, SSC (2dB) P-IFD, SSC (8dB) P-IFD, SSC (7dB) P-IFD, SSC (5dB) 3n-IFD (2dB) doc.: IEEE ax # of cumulated floors # of cumulated floors 5% enhancement of areal throughput by 3n-IFD with sufficient SIC 3% enhancement of areal throughput by P-IFD with sufficient SIC Noticeable areal throughput enhancement by SSC Slide 23

24 January 25 Outdoor Large BSS Scenario doc.: IEEE ax SLS Environment [5] BSSs layout 9 hexagonal grids of cells Inter cell distance (ICD) = 3m Location AP at the center of each cell 2 randomly distributed STAs / cell Heights: h AP =m, h STA =.5m Parameter Carrier Frequency : 2.4GHz Bandwidth : 2MHz Noise Figure : 7dB mode AP: 2 Tx and 2 Rx antennas STA: Tx and Rx antennas IFD mode AP: 2 shared antennas STA: shared antenna ICD Slide 24

25 January 25 Outdoor Large BSS Scenario doc.: IEEE ax SLS Environment (Contd.) General P-IFD Random deployment (uniform) Minimum distance b/w AP & STA : m Minimum distance b/w STAs : m SSC P-IFD Random deployment (uniform) Distance b/w AP & STA: m ~ y m Minimum distance b/w STAs : m SSC 3n-IFD Random deployment (uniform) Odd STA : random deployment within boundary Even STA : reflection of odd STA Distance b/w AP & STA: m ~ y m Slide 25

26 January 25 Outdoor Large BSS Scenario doc.: IEEE ax Evaluation Result () Throughput DL Throughput UL Throughput P-IFD, general (2dB).2 P-IFD, general (8dB) 3n-IFD (2dB). P-IFD, SSC (2dB) P-IFD, SSC (8dB) Throughput (bps) x 7 Max. throughput of IFD 2 x max. throughput of. SSC is effective to enhance throughput of IFD in low SINR regime Even with SSC, SIC more than 8dB required.4.3 P-IFD, general (2dB).2 P-IFD, general (8dB) 3n-IFD (2dB). P-IFD, SSC (2dB) P-IFD, SSC (8dB) Throughput (bps) x 7 Slide 26

27 January 25 Outdoor Large BSS Scenario doc.: IEEE ax Evaluation Result (2) Areal throughput Areal throughput (bps) 8 x DL Areal Throughput 9 P-IFD, general (2dB) P-IFD, general (db) 6 P-IFD, general (8dB) P-IFD, general (6dB) 4 P-IFD, SSC (2dB) P-IFD, SSC (db) 2 P-IFD, SSC (8dB) P-IFD, SSC (6dB) 3n-IFD (2dB) 8 6 Areal throughput (bps) 4 x UL Areal Throughput 9 P-IFD, general (2dB) P-IFD, general (db) 2 P-IFD, general (8dB) P-IFD, general (6dB) P-IFD, SSC (2dB) P-IFD, SSC (db) P-IFD, SSC (8dB) P-IFD, SSC (6dB) 8 3n-IFD (2dB) # of accumulated cells # of accumulated cells % areal throughput enhancement by 3n-IFD with sufficient SIC 3% areal throughput enhancement by P-IFD with sufficient SIC Noticeable areal throughput enhancement by SSC Slide 27

28 January 25 Summary doc.: IEEE ax Simultaneous transmission and reception is coming. When deployed in Wi-Fi networks, the system throughput with 8dB SIC case approached that with perfect SIC case (indoors). When STA density is low, extra SIC performance can further enhance the system throughput (outdoors). System level simulations show that with sufficient SIC performance, IFD leads to severalfold throughput enhancements compared to conventional half duplex counterpart. (Spatial) scheduling plays a key role to enhance performance of IFDbased Wi-Fi networks. If 4 times areal throughput enhancement is desired, adopting IFD is one of answers. Slide 28

29 January 25 doc.: IEEE ax References. IEEE 82.-3/42r, STR radios and STR media access. 2. IEEE 82.-3/22r, Considerations for In-Band Simultaneous Transmit and Receive (STR) Feature in Hew 3. IEEE 82.-4/838r, Discussion on Dual-Link STR in IEEE 82. ax 4. E. Everett, A. Sahai, and A. Sabharwal, Passive self-interference suppression for full-duplex infrastructure nodes, IEEE Trans. Wireless Commun., vol. 3, no. 2, pp , Feb IEEE 82.-4/98r4, TGax Simulation Scenarios. 6. DUPLO, D4..-Performance of full-duplex systems, duplo.eu/index.php/. Slide 29

30 January 25 doc.: IEEE ax Appendix Slide 3

January 25 doc.: IEEE 82.-5-43--ax MCS table Using IEEE 82.

31 January 25 doc.: IEEE ax MCS table Using IEEE 82.n Spatial streams = Bandwidth = 2MHz Residential Scenario 4ns GI Outdoor Large BSS Scenario 8ns GI MCS index Modulation type Coding rate Data rate (Mbits/s) 2MHz channel 8ns GI 4ns GI BPSK / QPSK / QPSK 3/ QAM / QAM 3/ QAM 2/ QAM 3/ QAM 5/ Slide 3

32 January 25 Other Simulation Results (2) SINR Residential Scenario doc.: IEEE ax DL SINR UL SINR Pairwise IFD(2dB) Pairwise IFD(7dB) 3 node form IFD(2dB) Pairwise IFD2(7dB) Pairwise IFD2(2dB) Pairwise IFD(2dB) Pairwise IFD(7dB) 3 node form IFD(2dB) Pairwise IFD2(2dB) Pairwise IFD2(7dB) SINR SINR DL with 2 db SIC, the SINR of pairwise IFD 5 db gain with SSC UL Increase of CCI between APs, Both IFD schemes show inferior performance to even with 2 db SIC Slide 32

33 January 25 Residential Scenario doc.: IEEE ax Other Simulation Results (3) Spectral Efficiency DL SE UL SE Pairwise IFD(2dB) Pairwise IFD(7dB) 3 node form IFD(2dB) Pairwise IFD2(2dB) Pairwise IFD2(7dB) Pairwise IFD(2dB) Pairwise IFD(7dB) 3 node form IFD(2dB) Pairwise IFD2(2dB) Pairwise IFD2(7dB) data rate x data rate x 7 Slide 33

34 (3m) (3m) (3m) UL Throughput, with BEST case data rate UL SE, with BEST case Pairwise IFD(2 Pairwise IFD(3 Pairwise IFD(4 Pairwise IFD( data rate x January 25 Outdoor Large BSS Scenario doc.: IEEE ax Other Simulation Results () (SSC,.SINR, 2. Thr, 3.SE) DL SINR, with BEST case SINR DL Throughput, with BEST case 3 node form IFD(2dB) (3m) (4m) (5m) 3 node form IFD(3m,2dB) 3 node form IFD(4m,2dB) 3 node form IFD(5m,2dB) data rate x 7.9 DL SE, with BEST case DL SINR, with BEST case 3 node form IFD(2dB) 3 node form IFD(3m,2dB) 3 node form IFD(4m,2dB) 3 node form IFD(5m,2dB) SINR (3m) (4m) (5m) DL Throughput, with BEST case data rate x 7.9 DL SE, with BEST case Pairwise IFD(2dB) Pairwise IFD(3m,2dB) Pairwise IFD(4m,2dB) Pairwise IFD(5m,2dB) DL SINR, with BEST case SINR DL Throughput, with BEST case Pairwise IFD(8dB) Pairwise IFD(3m,8dB) Pairwise IFD(4m,8dB) Pairwise IFD(5m,8dB) DL SINR, with BEST case Pairwise IFD(8dB) Pairwise IFD(3m,8dB) Pairwise IFD(4m,8dB) Pairwise IFD(5m,8dB) SINR Pairwise IFD(2dB) DL Throughput, with BEST case Pairwise IFD(3m,2dB) Pairwise IFD(4m,2dB) Pairwise IFD(5m,2dB) data rate x data rate x 7 DL SE, with BEST case DL SE, with BEST case UL SINR, with BEST case SINR.9.8 (3m) (4m) (5m) x UL SINR, with BEST case Pairwise IFD(8dB) Pairwise IFD(3m,8dB) Pairwise IFD(4m,8dB) Pairwise IFD(5m,8dB) SINR UL Throughput, with BEST case Pairwise IFD(8dB) Pairwise IFD(3m,8dB) Pairwise IFD(4m,8dB) Pairwise IFD(5m,8dB) data rate x 7 UL SE, with BEST case UL SINR, with BEST case Pairwise IFD(2dB) Pairwise IFD(3m,2dB) Pairwise IFD(4m,2dB) Pairwise IFD(5m,2dB) SINR UL Throughput, with BEST case Pairwise IFD(2dB) Pairwise IFD(3m,2dB) Pairwise IFD(4m,2dB) Pairwise IFD(5m,2dB) UL SE, with BEST case data rate x node form IFD(2dB) 3 node form IFD(3m,2dB).2 3 node form IFD(4m,2dB). 3 node form IFD(5m,2dB) data rate x (3m) (4m).3 (5m) data rate x Pairwise IFD(8dB).3 Pairwise IFD(3m,8dB) Pairwise IFD(4m,8dB).2 Pairwise IFD(5m,8dB) data rate x Pairwise IFD(2dB).3 Pairwise IFD(3m,2dB) Pairwise IFD(4m,2dB).2 Pairwise IFD(5m,2dB) data rate x (3m).5 (4m) (5m).4.3 Pairwise IFD(8dB).3 Pairwise IFD(3m,8dB).2.2 Pairwise IFD(4m,8dB) Pairwise IFD(5m,8dB) data rate data rate x 7 x 7 Slide 34

35 January 25 Outdoor Large BSS Scenario doc.: IEEE ax Other Simulation Results (2) SINR DL SINR UL SINR Pairwise IFD(2dB).2 Pairwise IFD(8dB) 3 node form IFD(2dB). Pairwise IFD2(8dB) Pairwise IFD2(2dB) SINR SINR Pairwise IFD(2dB) Pairwise IFD(8dB) 3 node form IFD(2dB) Pairwise IFD2(2dB) Pairwise IFD2(8dB) Slide 35

36 January 25 Outdoor Large BSS Scenario doc.: IEEE ax Other Simulation Results (2) Spectral Efficiency DL SE UL SE Pairwise IFD(2dB) Pairwise IFD(8dB) 3 node form IFD(2dB) Pairwise IFD2(2dB) Pairwise IFD2(8dB) Pairwise IFD(2dB) Pairwise IFD(8dB) 3 node form IFD(2dB) Pairwise IFD2(2dB) Pairwise IFD2(8dB) data rate x data rate 8 2 x 7 Slide 36

Wireless Communication

Wireless Communication Systems @CS.NCTU Lecture 14: Full-Duplex Communications Instructor: Kate Ching-Ju Lin ( 林靖茹 ) 1 Outline What s full-duplex Self-Interference Cancellation Full-duplex and Half-duplex