Abstract-When mobiles cannot support multiple antennas due to size or other constraints, conventional space-time coding cannot be used to provide uplink transmit diversity. To address this limitation, the concept of cooperation diversity has been introduced, where mobiles achieve uplink transmit diversity by relaying each other's messages. A particularly powerful variation of this principle is coded cooperation. Instead of a simple repetition relay, coded cooperation partitions the codewords of each mobile and transmits portions of each codeword through independent fading channels. This paper presents two extensions to the coded cooperation framework. First, we increase the diversity of coded cooperation in the fast-fading scenario via ideas borrowed from space-time codes. We calculate bounds for the bit-and block-error rates to demonstrate the resulting gains. Second, since cooperative coding contains two code components, it is natural to apply turbo codes to this framework. We investigate the application of turbo codes in coded cooperation and demonstrate the resulting gains via error bounds and simulations.
Abstract-We propose a new class of block codes that outperforms known space-time block codes at low rates. The new codes are designed by using appropriate rotations and set partitioning on two quasi-orthogonal codes, and combining subsets of their codewords. Using these techniques we are able to obtain higher coding gain at a given rate and improve performance. Simulations confirm the advantages of this code compared to other codes operating at the same rate and signal-to-noise ratio (SNR). We also provide an efficient maximum likelihood (ML) decoding algorithm for the new code.
Abstract-Concatenation of orthogonal space-time block codes (OSTBC) with an outer trellis has led to simple and powerful codes, known as superorthogonal codes or space-time block trellis-coded modulation. In this letter, we generalize these codes by finding new code supersets and corresponding set partitioning, resulting in improved coding gain. We provide design guidelines for the labeling of the generalized code trellises and demonstrate the gains by several example designs for two and four transmit antennas.
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