Performance Investigation of a UWB Relay System using Multiple Relays with Multiple Antennas in IEEE 802.15.3a Channel

Abstract

In order to coexist with existing legacy wireless systems, the transmit power spectral density (PSD) of ultra-wideband (UWB) impulse radio systems is limited. The coverage range of the UWB systems is then confined within a few meters. One possible way to achieve a greater coverage is a short-range multihop relaying strategy. This paper proposes a two-hop UWB relay system using multiple detect-and-forward relays, each of which is equipped with multiple antennas. Each multiple-antenna relay performs spatial diversity reception with partial-Rake scheme in the first hop, and decides whether or not to perform spatial transmit diversity with partial-pre-Rake scheme in the second hop. This leads not only to low complexity at the receiver, but also to reduced error propagation. Moreover, we derive the outage probability of the proposed relay system based on the IEEE 802.15.3a channel model. The effects of using multiple relay antennas, relays, and Rake/pre-Rake fingers on the outage performance are demonstrated. The tradeoffs among the numbers of relay antennas, relays, and Rake/pre-Rake fingers are also investigated. Numerical results show that it is best to use multiple relay antennas to improve the outage performance of the proposed system. Furthermore, in general, increasing the number of relays is more beneficial than increasing the number of Rake/pre-Rake fingers.

Ultra Wideband Systems with MIMO

“…Meanwhile, there has been increasing interest in the multi-relay transmissions (also known as cooperative relaying or virtual antenna arrays) [11,29,59,74,83,128,149,162,193,194,257,276]. However, most research studies have focused on the narrowband systems, and further investigations in the UWB case are still ongoing.…”

“…However, most research studies have focused on the narrowband systems, and further investigations in the UWB case are still ongoing. In [149], we presented a two-hop UWB system employing multiple DTF relays. It is found that, to avoid error propagation, the SNR threshold should be properly designed at each relay so that the relay is switched on only when the received SNR exceeds the threshold.…”

“…Note that each node considered in [9] is equipped with only a single antenna, while the 'space' refers to the multiple antennas across multiple nodes, including both the source and relay nodes. In [147,149], a multi-antenna relaying scheme is proposed, where multiple antennas are mounted at the relay node to increase the reliability of the relay by making use of the spatial diversity of the channels. Note that, in [149], the multiple antennas are used for the purposes of both reception and transmission at the relay node, and the gain thus obtained will be doubled compared with the cases in which these antennas are deployed either at the source node or at the destination node.…”

“…In [147,149], a multi-antenna relaying scheme is proposed, where multiple antennas are mounted at the relay node to increase the reliability of the relay by making use of the spatial diversity of the channels. Note that, in [149], the multiple antennas are used for the purposes of both reception and transmission at the relay node, and the gain thus obtained will be doubled compared with the cases in which these antennas are deployed either at the source node or at the destination node. Since UWB systems typically use Rake receivers to collect the energy spread over multipaths and the number of Rake fingers is an important factor which affects the complexity/cost of UWB systems, the compromise between the number of antennas at the relay node and the number of Rake fingers was investigated in [147,148].…”

Multi-hope relay based high capacity energy efficient model for ultra wideband communication system

“…Tabulated the parameters and mat lab code was given to produce the impulse response of modified S-V channel model. The performance of the relay system in terms of outage probability under IEEE 802.15.3a channel model has been discussed in [6]. Considered a detect-and-forward relay system with multiple antennas equipped in it.…”