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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 aj (45GHz) Authors/contributors: Date: 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 n and ac 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) Ts Ts-85Ts Ts-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

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) T c T c -85T c T 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

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] n-lb84-csd-text-proposal-submission. [2] ac-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, , pp

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


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