DocumentCode :
3084745
Title :
Multiple-Symbol Differential Sphere Decoding Aided Cooperative Differential Space-Time Spreading for the Asynchronous CDMA Uplink
Author :
Xu, Chao ; Ternon, Emmanuel ; Sugiura, Shinya ; Ng, Soon Xin ; Hanzo, Lajos
Author_Institution :
Sch. of ECS, Univ. of Southampton, Southampton, UK
fYear :
2011
fDate :
5-9 Dec. 2011
Firstpage :
1
Lastpage :
5
Abstract :
In this paper, we propose a Cooperative Differential Space-Time Spreading (CDSTS) scheme employing multiple relays, which eliminates the demanding requirement of channel estimation both at the relays and at the destination. More explicitly, the source node employs differential encoding during the first transmission interval, and the multiple relays perform Differential Space-Time Spreading (DSTS) based Amplify-and-Forward (AF) relaying in the second transmission interval. Eliminating high-complexity channel estimation is particularly important at the light-weight shirt-pocket-sized mobile handset based relays, since it is unrealistic to estimate the associated mobile-to-mobile channels, which would also pose a security threat and impose a Doppler-dependent pilot overhead. Finally, it would be prone to a channel-estimation-induced performance degradation, which might be close to the 3 dB non-coherent performance penalty. Loosely Synchronized (LS) CDMA spreading codes were adopted for the asynchronous CDMA uplink for the sake of achieving a near-single-user performance using a low-complexity single-user matched-filter detector. The potential performance degradation of the noncoherent receiver experienced in fast fading channels is mitigated by the proposed Multiple-Symbol Differential Sphere Decoding (MSDSD).
Keywords :
amplify and forward communication; channel estimation; code division multiple access; decoding; fading channels; mobile handsets; radio receivers; space-time codes; Doppler-dependent pilot overhead; amplify-and-forward relaying; asynchronous CDMA uplink; channel-estimation-induced performance degradation; cooperative differential space-time spreading; differential encoding; fast fading channels; light-weight shirt-pocket-sized mobile handset based relays; loosely synchronized CDMA spreading codes; low-complexity single-user matched-filter detector; mobile-to-mobile channels; multiple relays; multiple-symbol differential sphere decoding; near-single-user performance; noncoherent receiver; source node; transmission interval; AWGN; Encoding; Fading; Multiaccess communication; Peer to peer computing; Relays; Transmitting antennas;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Global Telecommunications Conference (GLOBECOM 2011), 2011 IEEE
Conference_Location :
Houston, TX, USA
ISSN :
1930-529X
Print_ISBN :
978-1-4244-9266-4
Electronic_ISBN :
1930-529X
Type :
conf
DOI :
10.1109/GLOCOM.2011.6134389
Filename :
6134389
Link To Document :
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