Abstract
In this article, a novel two-way double-relay selection strategy with its bit error rate (BER) performance analysis is proposed. In this novel strategy, as a first step we choose two relays out of a set of relay-nodes in a way to maximize the system performance in terms of BER and complexity. In the second step, the selected relays apply orthogonal space-time coding scheme using the three-phase protocol to establish a two-way communication between the transceivers, which will lead to a significant improvement in the achievable diversity and coding gain with a very low decoding complexity by using a symbol-wise decoder. Furthermore, the performance of the overall system is further enhanced through the use of a network coding method at the selected relay-nodes. Moreover, this paper proposes the analytical approximation of the BER performance. As well, we show that the analytical results match perfectly the simulated ones. In addition, we prove that our strategy outperforms the current state-of-the-art ones by proposing a better cooperative communication system in terms of BER.
Highlights
1 Introduction Multiuser interference and channel impairments such as multipath propagation and time-varying fading can affect the performance of wireless communications in terms of achievable data rate and bit error rate (BER) [1,2,3,4,5,6,7,8,9,10,11,12,13]
The use of distributed space-time coding techniques [2, 3, 8], distributed beam-forming techniques [4,5,6] and relay selection techniques [9,10,11,12,13,14,15,16,17,18,19,20,21,22] helps in reducing the impact of channel impairments and as a result enhancing the performance of wireless communication systems
It is very obvious that this relation is similar to that noticed in Fig. 8, the BER will improve while increasing the threshold value until the best performance is achieved at threshold value of two (Threshold = 2), the performance will degrade for threshold values greater than three
Summary
Multiuser interference and channel impairments such as multipath propagation and time-varying fading can affect the performance of wireless communications in terms of achievable data rate and bit error rate (BER) [1,2,3,4,5,6,7,8,9,10,11,12,13]. Through the use of orthogonal channels the relay-nodes can transmit the received signals, as well, they can encode them using orthogonal or non-orthogonal coding techniques Orthogonal coding techniques such as space-time coding (STC) enjoy a full diversity gain with low decoding complexity [13]. Once the successive difference becomes above the specified threshold (e.g., Threshold = 10%), this comparison will terminate, and the technique will move for further processing of the selected sub-group of relay-nodes (wg = 7, 6.95, 6.9, 6.85) At this stage, the proposed technique will estimate the expected performance of each node in the selected subgroup by multiplying the values of their both channels ( fi × bi ) to produce (7 × 8 = 56, 6.95 × 7.5 = 52, 6.9 × 20 = 138, and 6.85 × 25 = 171).
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