On Optimal Constellation Shaping for Wireless MIMO Relay Networks Based on Complex Field Network Coding

2014 ◽  
Vol 490-491 ◽  
pp. 1410-1414
Author(s):  
Xin Zhou ◽  
Yi Jun Guo ◽  
Jian Jun Hao

Network Coding (NC) is a promising technique that can maximize the network throughput. Multiple-Input-Multiple-Output (MIMO) detection technique is always combined with NC because they are both based on a similar system description. Two-way relay channel (TWRC) is the most common scene for the research on NC. However, TWRC is not a general case since it requires both users have information to exchange simultaneously. In this paper, a more general system model which adds a destination node is proposed. Based on this scene, for symmetrical and asymmetrical modulation schemes, we maximize the minimum Euclidean distance of the superposed constellation. The destination node never needs to have a packet exchange with the relay. Excellent performance has been proved by the theory analysis and simulation results.

2013 ◽  
Vol 427-429 ◽  
pp. 2584-2587 ◽  
Author(s):  
Zhan Mao Cao ◽  
Yuan Ping Zhang ◽  
Zhi Long Shan ◽  
Yun Cheng Jiang

A scheme to address router nodes is given for wireless Mesh Networks (WMN) with multiple input multiple output (MIMO) character. Both the wireless transceiver number of a node and geographical topology mesh contribute to wireless overlay model by placing link into different channel planes edge in case of interference. The triangular mesh is an important overlay topology for wireless networks. The router node addressing scheme keeps its instinct symmetric property. Several general cases over the addressing scheme are also discussed for the shortest routing path and the node coordination itself. The interference relation is abstracted into set models. Furthermore, the length of the shortest path is also given by a formula with the source node and destination node addresses. A general conclusion on relation of node address and hop count is also given.


2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Monchai Lertsutthiwong ◽  
Thinh Nguyen ◽  
Bechir Hamdaoui

We develop a framework that exploits network coding (NC) and multiple-input/multiple-output (MIMO) techniques, jointly together, to improve throughput of downlink broadcast channels. Specifically, we consider a base station (BS) equipped with multiple transmit antennas that serves multiple mobile stations (MSs) simultaneously by generating multiple signal beams. Given the large number of MSs and the small number of transmit antennas, the BS must decide, at any transmission opportunity, which group of MSs it should transmit packets to, in order to maximize the overall throughput. We propose two algorithms for grouping MSs that take advantage of NC and the orthogonality of user channels to improve the overall throughput. Our results indicate that the proposed techniques increase the achievable throughput significantly, especially in highly lossy environments.


Author(s):  
Shingo Yoshizawa ◽  
Yoshikazu Miyanaga

Multiple-input multiple-output orthogonal frequency multiplexing (MIMO-OFDM) is powerfulin enhancing communication capacity or reliance. The IEEE802.11n standard defines use of four spatial streams in spatial division multiplexing (SDM). The task group of IEEE802.11ac will extend it to eight spatial streams. We present an 88 MIMOOFDM baseband transceiver compatible with the IEEE802.11ac specification. Two 88 MMSE MIMO detectors based on Streassen’s matrix inversion have been designed for real-time MIMO detection. To demonstrate MIMO-OFDM transmission, we have prototyped a FPGA-based testbed in 22 MIMOOFDM for field experiment and video transmission.


2020 ◽  
Vol 71 (3) ◽  
pp. 222-226
Author(s):  
Zouhair Al-qudah

AbstractThe Gaussian multiple-input multiple-output (MIMO) orthogonal relay channel (ORC) is investigated. The transmission from source to relay is done over a channel that is orthogonal to source-destination and relay-destination channels. Practically, this assumption is made such that many communication devices from different technologies are exploited in relaying the source’s signal into its destination. For this channel model, the capacity is initially derived. Thereafter, we propose a transmission algorithm to achieve the derived capacity. Further, to support our theoretical results, many numerical examples are presented.


2017 ◽  
Vol 63 (3) ◽  
pp. 305-308
Author(s):  
Ramya Jothikumar ◽  
Nakkeeran Rangaswamy

AbstractThe breadth first signal decoder (BSIDE) is well known for its optimal maximum likelihood (ML) performance with lesser complexity. In this paper, we analyze a multiple-input multiple-output (MIMO) detection scheme that combines; column norm based ordering minimum mean square error (MMSE) and BSIDE detection methods. The investigation is carried out with a breadth first tree traversal technique, where the computational complexity encountered at the lower layers of the tree is high. This can be eliminated by carrying detection in the lower half of the tree structure using MMSE and upper half using BSIDE, after rearranging the column of the channel using norm calculation. The simulation results show that this approach achieves 22% of complexity reduction for 2×2 and 50% for 4×4 MIMO systems without any degradation in the performance.


2012 ◽  
Vol 195-196 ◽  
pp. 259-264
Author(s):  
Xin Yu Mao ◽  
Shu Bo Ren ◽  
Hai Ge Xiang

Detection is a major challenge for the utilization of multiple-input multiple-output (MIMO) system. Even the fixed sphere decoding (FSD), which is known for its simplicity in calculation, requests too much computation in high order modulation and large number antenna system especially for mobile battery-operated devices. In this paper, a reduced FSD algorithm is proposed to simplify the calculation complexity of the FSD while maintaining the performance at the same time. Simulation results in a 4×4, 16-QAM system show that up to 89% calculation can be saved while the performance drop is less than 0.1dB when SNR=24.


Author(s):  
Shirly Edward A. ◽  
Malarvizhi S.

CORDIC based improved real and complex QR Decomposition (QRD) for channel pre-processing operations in (Multiple-Input Multiple-Output) MIMO detectors are presented in this paper. The proposed design utilizes pipelining and parallel processing techniques and reduces the latency and hardware complexity of the module respectively. Computational complexity analysis report shows the superiority of our module by 16% compared to literature. The implementation results reveal that the proposed QRD takes shorter latency compared to literature. The power consumption of 2x2 real channel matrix and 2x2 complex channel matrix was found to be 12mW and 44mW respectively on the state-of-the-art Xilinx Virtex 5 FPGA.


2011 ◽  
Vol 225-226 ◽  
pp. 1225-1229
Author(s):  
Rui Zhe Yang ◽  
Li Zhang ◽  
Peng Bo Si ◽  
Zhi Kun Song ◽  
Yan Hua Zhang

For the classic three-node multiple-input multiple-output (MIMO) relay channel, a capacity enhanced transmission is proposed, using simple half-duplex tow-hop relaying based on symbol level decode-and-forward (DF) mode. For higher capacity to the destination, we assume the source node equipped with more antennas and propose the transmission strategy, where using channel precoding, the source transmits the data to the relay and destination respectively in the first hop and retransmits part of data to destination jointly with relay in the second hop. Additionally, the power allocation is designed to maximize the system capacity. Simulation results are then presented for illustration of the capacity enhancement.


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