Multi-Layer Broadcasting over a Block Fading MIMO Channel

Abstract

This paper introduces extensions for the broadcast approach for a multi-input multi-output (MIMO) block fading channel, with receiver only channel state information (CSI). Previous works have not been able to fully characterize the fundamental MIMO broadcasting upper bound. As it seems that analytical solution for this problem is quite difficult to achieve, we consider here sub-optimal schemes, for which achievable rates may be computed. In particular, finite level coding over a MIMO channel instead of continuous layering is analyzed, the expressions derived for the decoding probability regions allow numerical computation of finite level coding upper bounds. Noticing that the gains of two level coding over a MIMO channel are rather small, we consider sub-optimal techniques, which are more straightforward to implement. Among these techniques is the multiple-access channel (MAC) approach with single level coded streams, which is similar in concept to V-BLAST. Closed form expressions for probabilities of decoding regions here are derived, allowing numerical evaluation. We further consider multi-access permutation codes (MAPC). A Hadamard transform is compared with a suggested diagonal permutation code, which are shown to have similar performance, while diagonal permutation has lower implementation complexity. For all approaches, we derive information theoretic upper bounds of achievable rates.

Infinite-layer codes for single-user slowly fading MIMO channels

“…This is due to the possibility of partial data retrieving when multilayer codes are used. Note that all other transmission scheme proposed in [8] and [9] have inferior performance compared to R o .…”

“…Unfortunately, as stated, the resulted optimization problem does not appear to have a straightforward solution.Therefore, some suboptimal multi-layer transmission schemes are introduced and analyzed in [8]. In a follow up study, [9], the performance of some other suboptimal MIMO schemes including finite-layer coding strategies are investigated.…”

“…Similar to [8] and [9], in this work, we consider a singleuser slowly fading MIMO channel where the CSI is only available at the destination. However, instead of the suboptimal approaches in [8] and [9], we present a transmission scheme for the scenarios in which the receiver is only able to perform successive decoding.…”

“…However, instead of the suboptimal approaches in [8] and [9], we present a transmission scheme for the scenarios in which the receiver is only able to perform successive decoding. To this end, we first propose a design rule for constructing an infinite-layer code for MIMO channels.…”

The broadcast approach in communications systems

“…In the simple case of (5), the optimal power distribution has the following closed form solution where xo, Xl are determined by 1(xo) == P, 1(XI) == O. This extends to multiple-input single-output (MISO) and singleinput multiple-output (SIMO) channels [16]. Fig.…”