scholarly journals Dual-Hop OSTBC Transmissions Over Fading Channels under Receiver Phase Noise for Regenerative Systems

2012 ◽  
pp. 22-26
Author(s):  
K. Sujatha ◽  
S. Varadarajan
Keyword(s):  
Fading Channels ◽  
Channel Model ◽  
Spatial Diversity ◽  
Space Time ◽  
Delay Spread ◽  
Frequency Diversity ◽  
Space Time Coding ◽  
Propagation Parameters ◽  
Space Frequency ◽  
Time Coding

Space-time coding for fading channels is a Communication technique that realizes the diversity benefits of multiple transmit antennas. Previous work in this area has focused on the narrowband flat fading case where spatial diversity only is available. In this paper, we investigate the use of space-time coding in OFDM based broadband systems where both spatial and frequency diversity are available. We consider a strategy which basically consists of coding across OFDM tones and will therefore be called space-frequency coding. For a spatial broadband channel model taking into account physical propagation parameters and antenna spacing, we derive the design criteria for space-frequency codes and we show that space-time codes designed to achieve full spatial diversity in the narrowband case will in general not achieve full space-frequency diversity. Specifically, we show that the Alamouti scheme across tones fails to exploit frequency diversity. For a given set of propagation parameters and given antenna spacing, we establish the maximum achievable diversity order. Finally, we provide simulation results studying the influence of delay spread, propagation parameters, and antenna spacing on the performance of Space-frequency codes.

Space-Time Coding For Non-Coherent Cooperative Communications

2010 ◽  
pp. 352-380
Author(s):  
J. Harshan ◽  
G. Susinder Rajan ◽  
B. Sundar Rajan
Keyword(s):  
Fading Channels ◽  
Cooperative Communications ◽  
Channel Model ◽  
Space Time ◽  
Time Block ◽  
Relay Nodes ◽  
Space Time Coding ◽  
Space Time Block Codes ◽  
Time Coding ◽  
And Performance

Cooperative communication in a wireless network can be based on the relay channel model where a set of users act as relays to assist a source terminal in transmitting information to a destination terminal. Recently, the idea of space-time coding (STC) has been applied to wireless networks wherein the relay nodes cooperate to process the received signal from the source and forward them to the destination such that the signal received at the destination appears like a space-time block code (STBC). Such STBCs (referred as distributed space time block codes [DSTBCs]) when appropriately designed are known to offer spatial diversity. It is known that separate classes of DSTBCs can be designed based on the destination‘ s knowledge of various fading channels in the network. DSTBCs designed for the scenario when the destination has either the knowledge of only a proper subset of the channels or no knowledge of any of the channels are called non-coherent DSTBCs. This chapter addresses the problems and results associated with the design, code construction, and performance analysis (in terms of pairwise error probability [PEP]) of various noncoherent DSTBCs.

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