In this report we show how proper cooperation among radio nodes may provide diversity gain, also for single antenna systems. We consider first the connectivity of a wireless network and show how it can benefit from cooperation. Then, we consider some specific forms of cooperations, based on distributed space-time coding, in both single and multi-user contexts. Finally, we pay a special attentio...

A space-time coding method with low decoding complexity suitable for large numbers of antennas and high data rates is presented. High dimensionality is accommodated through use of a sub-optimal receiver that efficiently locates short vectors in a high-dimensional lattice. These vectors are used to approximate the transmitted symbol a-posteriori probabilities, which are refined by an outer seria...

Recently, space-time (ST) coding has emerged as one of the most promising technologies for meeting the challenges imposed by the wireless channel. This technology is primarily concerned with two-dimensional (2-D) signal design for multitransmit antenna wireless systems. Despite the recent progress in ST coding, several important questions remain unanswered. In a practical multiuser setting, one...

We study the energy-limited outage probability of the block space-time coding (STC)-based systems utilizing automatic repeat request (ARQ) feedback and adaptive power allocation. Taking the ARQ feedback costs into account, we derive closed-form solutions for the energy-limited optimal power allocation and investigate the diversity gain of different STCARQ schemes. Also, sufficient conditions ar...

We present a new space-time encoder based on packet-level redundancy which can increase the space-time encoder rate beyond unity without compromising diversity gains. A complementary low-complexity decoding algorithm based on maximum ratio combining and successive interference cancelation is further proposed. A major merit of the decoding algorithm is that it allows to adaptively tradeoff betwe...

A space-time physical-layer network coding (STPNC) method is presented for information exchange among multiple users over fully-connected multi-way relay networks. The method involves two steps: i) side-information learning and ii) space-time relay transmission. In the first step, different sets of users are scheduled to send signals over networks and the remaining users and relays overhear the...

Because of the gains like diversity, throughput, and the coverage extension provided by the multiple-input multipleout (MIMO) systems, it has been part of the various wireless communications standards. However, to reap the benefits offered by MIMO systems in size-constrained nodes, used in wireless communications, has been a challenging issue. To address this challenge, cooperative communicatio...