High-Rate, Single-Symbol ML Decodable Precoded DSTBCs for Cooperative Networks

Abstract

Distributed Orthogonal Space-Time Block Codes (DOSTBCs) achieving full diversity order and single-symbol ML decodability have been introduced recently by Yi and Kim for cooperative networks and an upperbound on the maximal rate of such codes along with code constructions has been presented. In this paper, we introduce a new class of Distributed STBCs called Semi-orthogonal Precoded Distributed Single-Symbol Decodable STBCs (S-PDSSDC) wherein, the source performs co-ordinate interleaving of information symbols appropriately before transmitting it to all the relays. It is shown that DOSTBCs are a special case of S-PDSSDCs. A special class of S-PDSSDCs having diagonal covariance matrix at the destination is studied and an upperbound on the maximal rate of such codes is derived. The bounds obtained are approximately twice larger than that of the DOSTBCs. A systematic construction of S-PDSSDCs is presented when the number of relays K ≥ 4. The constructed codes are shown to achieve the upperbound on the rate when K is of the form 0 or 3 modulo 4. For the rest of the values of K, the constructed codes are shown to have rates higher than that of DOSTBCs. It is shown that S-PDSSDCs cannot be constructed with any form of linear processing at the relays when the source doesn't perform co-ordinate interleaving of the information symbols. Simulation result shows that S-PDSSDCs have better probability of error performance than that of DOSTBCs.

Single real-symbol decodable, high-rate, distributed space-time block codes

“…The DOSTBCs [9] are single real-symbol decodable codes. Definition 4: Single complex-symbol decodable DSTBCs: A DSTBC is said to be single complex-symbol decodable [10] if the ML-metric can be expressed as follows.…”

“…Significant amount of research has been done on developing low ML-decoding complexity DSTBCs [6], [7], [8], [9], [10]. These DSTBCs are applicable when the relays do not have any channel state information (CSI).…”

“…The overall rate of transmission from the source to the destination is 2 2+k complex SPCU. The DSTBCs proposed in [10] are single complex-symbol decodable and the overall rate of these is upper bounded by 4 4+k complex SPCU for k relays. Here, the increase in rate with respect to the rate of the DOSTBCs comes at the cost of additional encoding complexity at the source and increased decoding complexity at the destination.…”

Cascaded orthogonal space–time block codes for wireless multi-hop relay networks

“…In prior work, maximum diversity gain achieving DSTBC constructions have been proposed for the twohop network [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], and for the multi-hop network [22][23][24]. Even though these DSTBC constructions achieve the maximum diversity gain, the decoding complexity of most of them, except [14][15][16][17][18][19][20][21], is very high, thereby limiting their use in practical deployment.…”

“…Even though these DSTBC constructions achieve the maximum diversity gain, the decoding complexity of most of them, except [14][15][16][17][18][19][20][21], is very high, thereby limiting their use in practical deployment. Construction of DSTBCs with low decoding complexity is practically important as highlighted by the fact that the Alamouti code is the most practically used code not only because it achieves the maximum diversity gain, but also because it requires minimum decoding complexity.…”