Layered Space-time Block Code Research Articles

Layered space–time block code for hybrid satellite–terrestrial broadcasting systems

SUMMARYMultiple‐input multiple‐output (MIMO) is a topic of high interest for the next generation of broadcasting systems. Even if they have begun to be proposed for the second generation of terrestrial digital TV, there are still gaps in the deployment of MIMO schemes in single‐frequency networks. This deployment becomes more critical when a hybrid satellite–terrestrial transmission is adopted because of the different aspects of the respective transmission links. In this paper, we propose to apply a layered space–time block code (LSTBC) for MIMO schemes in this hybrid transmission for next‐generation handheld (NGH) systems. The contribution of this paper is multi‐fold. First, we detail the land mobile satellite channel specifications describing the satellite link. Then, we propose to apply a MIMO scheme between the antennas of the satellite site and the terrestrial site. Then, we introduce the LSTBC scheme for NGH broadcasting systems. The proposed code is based on a layered construction designed to be efficient in shadowing regions. This efficiency is verified in a line‐of‐sight situation but also in low, moderate and deep shadow situations. The LSTBC scheme is then a very promising candidate for NGH systems with MIMO transmission. Copyright © 2012 John Wiley & Sons, Ltd.

A Symbol-wise Ordered Successive Interference Cancellation Detector for Layered Space-Time Block Codes

We propose a detector for MLSTBC (Multilayered Space-Time Block Codes), which applies the global optimization to minimize the total square error. The proposed detector for MLSTBC compares the total square errors of all signals for each possible detection order, to choose the detection order with the smallest total square errors. It improves the performance of the existing detector for MLSTBC. With respect to the existing detector for MLSTBC, the proposed detector for MLSTBC has the performance gain of about 0.8 dB at BER=10-2.

A new ML based interference cancellation technique for layered space-time codes

This paper presents a new and simple decoding algorithm for layered space time block codes such as the two independent Alamouti's codes which are also called the double space-time transmit diversity (DSTTD) system. By using group interference suppression and successive interference cancellation, we can treat DSTTD as two independent space-time block codes (STBC). We can then decode both of these STBC's through a simple maximum likelihood (ML) detector with null space-based interference cancellation. We also compare the proposed interference cancellation (IC) scheme with the conventional MMSE IC scheme. The performance of the proposed IC scheme is comparable to that of the MMSE IC scheme while the complexity reduction factor of the proposed scheme can be up to 5 compared to the MMSE IC scheme.

A quasi-orthogonal group space-time architecture to achieve a better diversity-multiplexing tradeoff

Most existing MIMO (multiput-input multiput-output) schemes optimize only either the diversity gain or the multiplexing gain. To obtain a good tradeoff between these two, the quasi-orthogonal group space-time (QoGST) architecture is proposed, wherein the transmit stream is subgrouped but encoded via an inter-group space-time block encoder, with group interference suppression at the receiver. This paper also considers another combined space-time coding and layered space-time architecture, which we refer to as group layered space-time (GLST), where space-time block coding is employed within each group. Under the assumption of Rayleigh fading and a prior perfect channel state information at the receiver, a performance analysis will demonstrate that both QoGST and GLST can achieve a good diversity-multiplexing tradeoff. QoGST is even superior to GLST. Simulation results will validate our analysis and further show that compared to the existent layered space-time block code (LSTBC) scheme, both QoGST and GLST can achieve a significant performance gain.