doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Joint Coding and Modulation Diversity for the Next Generation WLAN Date: Authors: Slide1

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Slide2 Abstract The combination of OFDM and MIMO is still a key feature for high- throughput transmission in the next generation WLAN. An improved MIMO-OFDM scheme based on modulation diversity named Joint Coding and Modulation Diversity (JCMD) is proposed. It can take full advantage of the coding-gain, the frequency diversity of OFDM system and the spatial diversity of MIMO all together. Simulation results turn out that it can obtain obvious SNR gain as compared with the current BICM-MIMO scheme, which is up to 7dB.

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Slide3 Background IEEE ac greatly enhanced the air interface key technologies, such as enhanced LDPC coding and tone mapper, multiuser (MU) MIMO, broader bandwidth up to 160MHz, higher order quadrature amplitude modulation (QAM) modulation up to 256QAM and more transmit antenna number up to 8. [1] had proposed that the system capacity of 10 G bit/s will be achieved by combining some possible technologies for the next generation WLAN. The system capacity should be improved to maintain high performance. –Higher peak data rate extend the bandwidth/channel, e.g. 320 MHz/ch The next generation WLAN will support more spatial streams support more users in a MU-MIMO transmission –Higher spectrum efficiency DL-OFDMA Advanced SDMA

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission JCMD-MU-MIMO Transmit Diagram Slide 4 NOTES –The blocks drawn in dotted line are our proposed additional processing on the basis of the current ac standard scheme. –In simulations, the spatial mapping method for SU and MU MIMO are SVD and BD precoding, respectively.

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Rotational Modulation – Maximized modulation diversity order. – The relationship between conventional modulated complex symbol A + j*B and the rotational modulated complex symbol X + j*Y can be expressed as: Joint Coding and Modulation Diversity Slide 5 QPSK R-QPSK L=1 L=2

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Optimum rotational matrices are proposed as follows Proposed Rotational Matrices Slide 6 ModulationRotational Matrix QPSK 16 QAM 64 QAM 256 QAM

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Q-Component Interleaver – Spatial Q-Interleaving Let and denote the input Q-component and the output Q-component of the spatial Q-interleaver on the spatial stream at the t instant. The spatial Q- interleaving is defined as follows, where is the spatial stream number. (1) – Frequency domain Q-Interleaving On each spatial stream, the frequency domain Q-Interleaving is carried out as follows, where is the OFDM subcarrier number. (2) Joint Coding and Modulation Diversity Slide 7

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Simulation Parameters for ac SU-MIMO Scheme Slide 8 ParametersValues PHY schemeOFDM Antenna scheme2*2, 4*4 Bandwidth20 MHz Length of FFT64 Number of subcarriers56 Number of data subcarriers52 Code TypeBCC, LDPC Channel Model802.11ac channel model MCSsMCS2, MCS4, MCS7, MCS8 Sub-carrier spacing312.5 kHz Channel estimationPerfect CSI

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission FER performance for 2*2 SU-MIMO scheme in AC Channel, case E, NLOS Slide 9 MCS SNR Gain in dB (FER=0.01) BCCLDPC MCS MCS MCS MCS

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission FER performance for 4*4 SU-MIMO scheme in AC Channel, case E, NLOS Slide 10 MCS SNR Gain in dB (FER=0.01) MCS27.2 MCS44.2

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Simulation Parameters for ac MU-MIMO Scheme Slide 11 ParametersValues PHY schemeOFDM User number2 The number of antennas at TX4 The number of antennas at RX per user2 Bandwidth20 MHz Length of FFT64 Number of subcarriers56 Number of data subcarriers52 Code typeBCC, LDPC Channel model802.11ac channel model MCSsMCS2, MCS4, MCS7, MCS8 Sub-carrier spacing312.5 kHz PrecodingBD Channel estimationPerfect CSI

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission FER performance for MU-MIMO scheme in AC Channel, case E, NLOS, 2 users, each user has 2 spatial streams. Slide 12 MCS SNR Gain in dB (FER=0.01) BCCLDPC MCS24.2 MCS

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Hardware prototype system Slide 13 ParametersValues Carrier frequency (GHz) Bandwidth (MHz)4.0 Sampling frequency (MHz)3.84 Sampling interval (ns)260 FFT256 Sub-carrier spacing (kHz)15 OFDM symbol interval (us)75 GI interval (us)8.33 Number of OFDM symbols in 5ms frame 66 (1*preamble symbols)

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Slide 14 Channel estimation SNR Gain in dB (FER=0.01) LS3 LMMSE3 FER performance for Hardware prototype system in VA channel ParametersValues Number of transmit antenna2 Number of receive antenna2 Channel codingLDPC Code rate3/4 ModulationQPSK Channel modelVA Channel estimationLS, LMMSE Hardware prototype system has significant performance advantage about 3 dB.

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Slide 15 Complexity Analysis The overall complexity of the proposed JCMD scheme is almost the same as the conventional BICM scheme. The total number of addition/subtraction and multiplication/division operations is used to represent the overall complexity base on the hardware prototype system. Conventional schemeJCMD schemeProportion QPSK : QAM : QAM :1.0201

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission Conclusions JCMD scheme jointly optimizes the MIMO-OFDM, channel coding and modulation together, which makes full use of time, frequency and space diversity. –Rotational modulation –Q-components interleaver The proposed scheme can obtain obvious SNR gain (up to 7dB) as compared with the current BICM MIMO scheme in IEEE standard for LDPC/BCC coding, all MCSs and various channels. –Significant SNR gain Larger coverage area Lower transmit power –Low complexity Low processing power and cost JCMD is suitable for the next generation WLAN. Slide 16

doc.: IEEE /0112r0 Zhanji Wu, et. Al. January 2013 Submission References [1] wng-improved-spectrum-efficiency-for-the-next- generation-wlans.pptx [2] ah-Channel-Model-Text.docx [3] 3GPP TR Technical Specification Group Radio Access Network; Spatial channel model for Multiple Input Multiple Output (MIMO) simulations [4] ah-tgah-Introductory-proposal.ppt [5] ac-joint-coding-and-modulation-diversity-to ac.ppt [6] ah-specification-framework-for-tgah.docx Slide 17