Rotation Modulation Application to 802.11ac system January 2010 doc.: IEEE 802.11-10/0084r3 Rotation Modulation Application to 802.11ac system Date: 2010-11-8 Authors: Brian Hart, Cisco Systems

Abstract Rotation modulation technique for QPSK has already been adopted in 802.11ad system. Based on our recent research, this technique can also improve the overall performance of 802.11ac system.

Our Proposed Scheme Encode Rotational Mod. OFDM Space-Time-Freq Interleaver ( I/Q Separate) Precoding OFDM Encode Rotational Mod. CSI Estimation 1 Introduce rotational modulation matrices for 4/16/64/256 QAM 2 Introduce space/time/frequency I/Q separate interleaver

Our Proposed Rotation Matrix to 802.11ac system Modulation Proposed Rotation Matrix QPSK 16QAM 64QAM 256QAM

Simulation Parameters Values PHY scheme OFDM Antenna scheme 2*2 ,4*4,8*8 Length of FFT 64 Number of subcarriers 57 Code Type LDPC, CC Code Rate 3/4, 5/6 Modulation Type QPSK 16QAM 64QAM 256QAM Channel Type TGac Channel Model E LOS,NLOS[4,5]

Rotation Modulation LOS (2*2),LDPC

Gain of Rotation Modulation (LOS2*2),LDPC MCS MODULATION CODE RATE GAIN (dB) (FER=0.01) 2 QPSK 3/4 7.2 4 16-QAM 4.8 7 64-QAM 5/6 4.5 8 256-QAM 1.8

Rotation Modulation LOS (2*2),CC

Gain of Rotation Modulation (LOS2*2),CC MCS MODULATION CODE RATE GAIN (dB) (FER=0.01) 2 QPSK 3/4 7.4 4 16-QAM 5.6 7 64-QAM 5/6 5.2 8 256-QAM 2.3

Rotation Modulation NLOS(4*4) ,CC

Gain of Rotation Modulation (NLOS4*4),CC MCS MODULATION CODE RATE GAIN (dB) (FER=0.01) 2 QPSK 3/4 5.2 4 16-QAM 4.4 7 64-QAM 5/6 4.1 8 256-QAM 1.5

Rotation Modulation NLOS(8*8) ,CC

Gain of Rotation Modulation (NLOS8*8),CC MCS MODULATION CODE RATE GAIN (dB) (FER=0.01) 2 QPSK 3/4 3.2 4 16-QAM 2.8 7 64-QAM 5/6 3.3 8 256-QAM 1.5

Effect of phase noise 2.2 2.3 2.4 2.6 MCS2 Gain（db）（FER=0.01） No PN(Ideal) 2.2 With PN(Ideal) 2.3 No PN(LS) 2.4 With PN(LS) 2.6

June 2010 doc.: IEEE 802.11-10/xxxxr0 Conclusions No matter LOS or NLOS channel, No matter LDPC Coding or Convolutional Coding, rotational modulation has obvious performance gain over conventional modulations, which is up to 7 dB. For different antenna schemes,2*2 antenna scheme can achieve the largest relative gain; for 4 * 4 and 8 * 8, it also can obtain remarkable gain. Rotational modulation is robust for phase noise. In a word, based on our proposal, rotation modulation is also applicable to 802.11ac system. Brian Hart, Cisco Systems

References 1. IEEE P802.11 Wireless LANs PHY/MAC Complete Proposal Specification, 2010-05-18 2. J.Boutros, E.Viterbo, Signal Space Diversity: a power and bandwidth efficient diversity technique for the Rayleigh fading channel. IEEE Trans. Inform.Theory, vol.44. pp.1453-1467, July 1998 . 3. Wu Zhanji, A novel Coding-Rotated-Modulation OFDM scheme, International Conference on Communication Technology and Application 2009, ICCTA 2009, October, 2009, pp:517-520 4. Erceg, V. et al. “TGn Channel Models.” Doc. IEEE802.11-03/940r4. 5. Breit, G. et al., “TGac Channel Model Addendum,” Doc. IEEE 802.11-09/0308r12