Reliability-based Detection of Variable-rate Space-time Block Codes
Wireless Communications , Variable-Rate Space-Time Block Codes , MIMO Systems , Near-ML Detection
We present a new sub-optimal near-maximum-likelihood (ML) detection method for the family of variable-rate space-time block codes (VRSTBC). The proposed detection method is based on the concept of symbol reliability and provides a wide range of performance-complexity trade-offs. The reliability measures are defined with the help of a recent generic ML metric expression. The error performance and complexity analysis of the method via simulations show an achievable near-ML error performance with significant reduction in complexity. The performance of the proposed method is also compared with the group interference cancellation (GIC) method which was the detection method originally applied to VRSTBCs and the results show a significant improvement. The new method offers various levels of error protection via a simple parameter and hence can provide the users of a wireless network with different performance levels according to their cost allowance. Unequal error protection by VRSTBCs under the new detection method was explored. Several applications integrating data with different levels of sensitivity to error can benefit from the wide range of possibilities that the combination of the proposed detection method and VRSTBCs provides. To further explore these flexibilities, four practically interesting power allocation schemes were applied to the transmission and the behaviors were observed through case studies.