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Distributed differential space-time spreading for the asynchronous relay aided interference-free cooperative CDMA uplink

Distributed differential space-time spreading for the asynchronous relay aided interference-free cooperative CDMA uplink
Distributed differential space-time spreading for the asynchronous relay aided interference-free cooperative CDMA uplink
In this paper, we propose a differential Space-Time Coding (STC) scheme designed for asynchronous cooperative networks, where neither channel estimation nor symbol-level synchronization is required at the cooperating nodes. More specifically, our system employs differential encoding during the broadcast phase and a Space-Time Spreading (STS)- based amplify-and-forward scheme during the cooperative phase in conjunction with interference rejection Direct Sequence (DS) spreading codes, namely Loosely Synchronized (LS) codes. The LS codes exhibit a so-called Interference Free Window (IFW), where both the auto-correlation and cross-correlation values of the codes become zero. The IFW allows us to eliminate both the Multi-User Interference (MUI) as well as the potential dispersion-induced orthogonality degradation of the cooperative space-time codeword and the interference imposed by the asynchronous transmissions of the relay nodes. Furthermore, the destination node can beneficially combine both the directly transmitted and the relayed symbols using low-complexity correlation operations combined with a hard-decision detector. Our simulation results demonstrate that the proposed Cooperative Differential STS (CDSTS) scheme is capable of combating the effects of asynchronous uplink transmissions without any Channel State Information (CSI), provided that the maximum synchronization delay of the relay nodes is within the width of IFW. It will be demonstrated that in the frequency-selective environment considered our CDSTS arrangement is capable of exploiting both space-time diversity and multi-path diversity with the aid of a RAKE combiner.
5 pages
Sugiura, Shinya
4c8665dd-1ad8-4dc0-9298-bf04eded3579
Chen, Sheng
9310a111-f79a-48b8-98c7-383ca93cbb80
Hanzo, Lajos
66e7266f-3066-4fc0-8391-e000acce71a1
Sugiura, Shinya
4c8665dd-1ad8-4dc0-9298-bf04eded3579
Chen, Sheng
9310a111-f79a-48b8-98c7-383ca93cbb80
Hanzo, Lajos
66e7266f-3066-4fc0-8391-e000acce71a1

Sugiura, Shinya, Chen, Sheng and Hanzo, Lajos (2010) Distributed differential space-time spreading for the asynchronous relay aided interference-free cooperative CDMA uplink. At ICC 2010 ICC 2010, South Africa. 23 - 27 May 2010. 5 pages.

Record type: Conference or Workshop Item (Paper)

Abstract

In this paper, we propose a differential Space-Time Coding (STC) scheme designed for asynchronous cooperative networks, where neither channel estimation nor symbol-level synchronization is required at the cooperating nodes. More specifically, our system employs differential encoding during the broadcast phase and a Space-Time Spreading (STS)- based amplify-and-forward scheme during the cooperative phase in conjunction with interference rejection Direct Sequence (DS) spreading codes, namely Loosely Synchronized (LS) codes. The LS codes exhibit a so-called Interference Free Window (IFW), where both the auto-correlation and cross-correlation values of the codes become zero. The IFW allows us to eliminate both the Multi-User Interference (MUI) as well as the potential dispersion-induced orthogonality degradation of the cooperative space-time codeword and the interference imposed by the asynchronous transmissions of the relay nodes. Furthermore, the destination node can beneficially combine both the directly transmitted and the relayed symbols using low-complexity correlation operations combined with a hard-decision detector. Our simulation results demonstrate that the proposed Cooperative Differential STS (CDSTS) scheme is capable of combating the effects of asynchronous uplink transmissions without any Channel State Information (CSI), provided that the maximum synchronization delay of the relay nodes is within the width of IFW. It will be demonstrated that in the frequency-selective environment considered our CDSTS arrangement is capable of exploiting both space-time diversity and multi-path diversity with the aid of a RAKE combiner.

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More information

Published date: May 2010
Additional Information: Event Dates: May 23-27, 2010
Venue - Dates: ICC 2010, South Africa, 2010-05-23 - 2010-05-27
Organisations: Southampton Wireless Group

Identifiers

Local EPrints ID: 271203
URI: https://eprints.soton.ac.uk/id/eprint/271203
PURE UUID: 0d765763-de02-435f-ae37-f90d6cfeba74
ORCID for Lajos Hanzo: ORCID iD orcid.org/0000-0002-2636-5214

Catalogue record

Date deposited: 28 May 2010 12:08
Last modified: 06 Jun 2018 13:15

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Contributors

Author: Shinya Sugiura
Author: Sheng Chen
Author: Lajos Hanzo ORCID iD

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