MIMO Network Coding Research Articles

Two-layer MIMO Network Coding based Scheme for Cooperative Communications

In this contribution, we propose and investigate a novel scheme of two-layer multi-input multi-output (MIMO) systems employing network coding in the scenario of cooperative communication. The first MIMO layer of our system is constituted from an Irregular Convolutional Coded Unity Rate Coded Space Time Trellis Coded M-ary Phase Shift Keying (IrCC-URC-STTC-MPSK) schemes. The MIMO coding scheme is designed with the aid of Extrinsic Information Transfer (EXIT) charts for approaching the corresponding channel capacity in fast fading environment. The second Network Coding based Virtual-MIMO layer is incorporated into our system for coping with the bad effect of slow fading channels, which may not be handled by the first MIMO coding layer. Based on simulation results, our proposed scheme outperforms the conventional MIMO systems, where no cooperation is invoked for exploiting the diversity gain brought by the aiding of other users available in the system.

Joint Virtual MIMO and Network Coding Scheme with Superposition ARQ in Relay System

A new two-way transmission protocol termed VMNC-SARQ (Virtual MIMO Network Coding with Superposition ARQ) was proposed in this paper, which could improve throughput efficiency of DF (Decode-and Forward) relay network signally. In first step, two single-antenna nodes send messages to the double-antenna relay station simultaneously by using a method similar to 2×2 VBLAST (Vertical Bell Laboratories Layered Space Time) system. In step two, relay station processes the decoded signals received from two source nodes through Network Coding, and then broadcasts the combined messages with Alamouti Coding. A novel retransmission strategy will be implemented when demodulation and decoding failure presents. In order to reduce retransmission overhead, we attach the retransmitted packet to the latter normal packet by using higher modulation, and exploit the confidence value of previously error packet to help to recover both packets. Theoretical analysis and simulation results show that the proposed scheme could greatly improve end-to-end throughput efficiency for two-way relaying systems DOI : http://dx.doi.org/10.11591/telkomnika.v12i2.3444

Optimization of Network Coded MIMO Transmission in Multiple-Access Relay Network

We consider a multiple-access relay network where multiple source nodes send independent packets to a common destination with the assistance of multiple relay nodes. We assume that the relay nodes are equipped with multiple antennas and are allowed to choose either spatial multiplexing (SM) or transmit diversity (TD) in sending network coded packets. We verify the performance limit of conventional MIMO network coding and propose two optimization schemes to overcome this limit. To this end, we develop an integrated design methodology that jointly optimizes the redundancy offered by network coding at the relays and channel coding at the sources as well as the spatial redundancy offered by multiple antennas in order to minimize the end-to-end outage probability. We show that such joint optimization can provide a significant energy saving.

Packet scheduling with joint design of MIMO and network coding

In this paper, we propose a joint design of MIMO technique and network coding (MIMO-NC) and apply it to improve the performance of wireless networks. We consider a system in which the packet exchange among multiple wireless users is forwarded by a relay node. In order to enjoy the benefit of MIMO-NC, all the nodes in the network are mounted with two antennas and the relay node possess the coding capability. For the cross traffic flows among any four users, the relay node not only can receive packets simultaneously from two compatible users in the uplink (users-to-relay node), but also can mix up distinct packets for four destined users into two coded packets and concurrently send them out in the same downlink (relay node-to-users), so that the information content is significantly increased in each transmission. We formalize the problem of finding a schedule to forward the buffered data of all the users in minimum number of transmissions in such a system as a problem of finding a maximum matching in a graph. We also provide an analytical model on maximum throughput and optimal energy efficiency, which explicitly measures the performance gain of the MIMO-NC enhancement. Our analytical and simulation results demonstrate that system performance can be greatly improved by the efficient utilization of MIMO and network coding opportunities.

MIMO Network Coding-Based PHY/MAC Protocol for Replacement of CSMA/CA in Efficient Two-Way Multihop Relay Networks

Backbone wireless mesh networks have attracted much of attention due to their wide-range applications. The use of CSMA/CA basedMAC protocols in mesh networks, however, leads to an inefficient resource utilization, and to high latency. Several alternative protocols including directional MAC, multichannel MAC only provide marginal improvement. Recently, a cross-layer design employing multiple antenna techniques and network coding called MIMO network coding was proposed. Owing to multiple access interference cancellation ability of MIMO, bi-directional flow multiplexing capability of network coding in combination with an efficient channel access scheme of TDMA/TDD, MIMO two-way relay provides significantly high end-to-end capacity. In this paper, MIMO network coding is considered as an alternative PHY/MAC protocol of CSMA/CA. This paper provides details of the protocol and develops network simulators for performance evaluation. Furthermore, an efficient retransmission scheme for transmission system employing network coding is proposed. The paper shows that MIMO network coding achieves significant network performance improvement with respect to CSMA/CA mesh networks. The proposed retransmission scheme is also shown to be effective in terms of resource usage as well as QoS guarantee.

STBC MIMO Network Coding for Bi-directional Multi-Hop Relay Networks

Efficient bi-directional multi-hop wireless networks based on MIMO algorithm or network coding have been proposed in recent papers. This paper proposes a new technique named as MIMO network coding, that is a combination of network coding and MIMO algorithm for multi-hop relay networks. By using MIMO network coding, co-channel interference cancellation and efficient bi-directional transmission can be realized simultaneously with lower complexity in multi-hop networks. Moreover, Space Time Block Code (STBC) MIMO transmission is also introduced to achieve higher reliability in MIMO network coding. It is confirmed from numerical analysis that the MIMO network coding with STBC achieves higher capacity and reliability than conventional schemes.

2D MIMO Network Coding with Inter-Route Interference Cancellation

Infrastructure wireless mesh network has been attracting much attention due to the wide range of its application such as public wireless access, sensor network, etc. In recent years, researchers have shown that significant network throughput gain can be achieved by employing network coding in a wireless environment. For further improvement of network throughput in one dimensional (1D) topology, Ono et al. proposed to use multiple antenna technique combined with network coding. In this paper, being inspired by MIMO network coding in 1D topology, the authors establish a novel MIMO network coding algorithm for a 2D topology consisting of two crossing routes. In this algorithm, multiple network coded flows are spatially multiplexed. Owing to the efficient usage of radio resource of network coding and co-channel interference cancellation ability of MIMO, the proposed algorithm shows an 8-fold gain in network capacity compared to conventional methods in the best-case scenario.