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Doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 1 Shiwen He , Haiming Wang Cyclic Shift Diversity Design for IEEE 802.11aj (45GHz) Authors/contributors:

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Presentation on theme: "Doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 1 Shiwen He , Haiming Wang Cyclic Shift Diversity Design for IEEE 802.11aj (45GHz) Authors/contributors:"— Presentation transcript:

1 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 1 Shiwen He , Haiming Wang Cyclic Shift Diversity Design for IEEE 802.11aj (45GHz) Authors/contributors: Date: 2015-01-21 Presenter: Shiwen HE

2 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 2 Shiwen He , Haiming Wang Background Cyclic shift diversity (CSD) is a simple and valid strategy that can be used to achieve spatial diversity. CSD can reduce the effects of unintended beamforming when correlated signals are transmitted in multiple space-time streams. CSD can be achieved straightforwardly by introducing different cyclic shifts to every part of the OFDM symbols or blocks in SC systems. 802.11n and 802.11ac defined their CSD table values respectively.

3 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 3 Shiwen He , Haiming Wang Introduction In OFDM scenario: - Cyclic delays are introduced to the effective parts of the OFDM symbols, illustrated as following. In SC scenario: - Cyclic delays are introduced to the parts of the blocks, illustrated as following.

4 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 4 Shiwen He , Haiming Wang The Optimization of CSD values : - When applying cyclic delay, the signal received via multiple transmitting antennas in frequency domain is where is the cyclic delay value at the transmitter antenna , and is the number of transmitter antenna, is the addictive noise. - The cyclic delays can be seen respectively as phase rotations introduced to the channel frequency response

5 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 5 Shiwen He , Haiming Wang - It is assumed that the composite channels have similarly stochastic properties, expressed by a common correlation function is a random gap of frequency. - Then the correlation function of the composite channels can be expressed as Since then which implies that the correlation is reduced.

6 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 6 Shiwen He , Haiming Wang - With selecting appropriately, it is possible to force a zero in the correlation function and to introduce better diversity to the composite channel. where F is the sub-carrier spacing, and l, m are integer variables. - Such a result is achieved for delays

7 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 7 Shiwen He , Haiming Wang Four sub-channels realization of 4x1 system(OFDM):

8 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 8 Shiwen He , Haiming Wang Equivalent channel realization of 4x1 system(OFDM): Without CSDApplying CSD

9 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 9 Shiwen He , Haiming Wang CSD Table for OFDM Data field : T CS (n) values for the data fields of a PPDU N STS,total Cyclic shift for space-time stream n (ns) 1234 1 0--- 20-128Ts-- 30-170Ts-85Ts- 40-128Ts-64Ts-192Ts

10 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 10 Shiwen He , Haiming Wang CSD cont: Spatial Extending for OFDM : N STS N Tx QkQk 12 14 24 34

11 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 11 Shiwen He , Haiming Wang CSD Table for SC Data field : T CS (n) values for the data fields of a PPDU N STS,total Cyclic shift for space-time stream n (ns) 1234 1 0--- 20-128T c -- 30-170T c -85T c - 40-128T c -64T c -192T c

12 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 12 Shiwen He , Haiming Wang CSD cont: Spatial Extending for SC : N STS N Tx QkQk 12 14 24 34

13 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 13 Shiwen He , Haiming Wang Simulation Comparisons of error performance of the 2x1 OFDM system with QPSK Modulation and 1/2-rate.

14 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 14 Shiwen He , Haiming Wang Comparisons of error performance of the 2x1 SC system with QPSK Modulation and 1/2-rate.

15 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 15 Shiwen He , Haiming Wang Conclusion With QPSK modulation and 1/2-rate, PER performance can be improved about 1dB at the PER of 0.1 by using the proposed CSD table values. Compared with STBC, the proposed CSD scheme loses a little gain with QPSK modulation and 1/2-rate. However, CSD scheme has low additional complexity. The proposed CSD table values can be applied to the data field of the OFDM or SC scenario.

16 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 16 Shiwen He , Haiming Wang References [1] 11-06-0952-01-000n-lb84-csd-text-proposal-submission. [2] 11-10-1301-00-00ac-legacy-csd-table-for-11ac. [3] K. Witrisal, Y.-H. Kim and R. Prasad, “Antenna diversity for OFDM using cyclic delays”, Benelux: Roc. SCVT-2001, 2001.10, pp. 13-17.

17 doc.: IEEE 11-15/0210r0 Submission September 2014 Slide 17 Shiwen He , Haiming Wang Thanks for Your Attention.


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