Adaptive Network Coded Cooperation Research Articles

A Group Cooperative Coding Model for Dense Wireless Networks

Generally, node groups in dense wireless networks (WNs) often pose the problem of communication between the central node and the rest of the nodes in a group. Adaptive Network Coded Cooperation (ANCC) for wireless central node networks adapts precisely to an extensive and dense WN, at this level the random linear network coding (RLNC) scheme with Low-Density Parity-Check (LDPC) are used as the essential ANCC evolution. This paper suggests two phases effective technique then studies the influence of the randomly chosen number of coded symbols which are correctly received in the second phase on bit error rate (BER). The proposed technique also focuses on the role of dispersion impact related to the LDPC code generating matrix. The results of the simulation allow selecting the best compromise for the best BER.

Enhanced Adaptive Network Coded Cooperation for Wireless Networks

Adaptive network coded cooperation (ANCC) provides a general coded cooperation framework to map the communication connections of a wireless network into the coding constraint. However, random selection policy is assumed at each node to select its retrieval subset, which cannot avoid illness in code graph at the sink. In this paper, the concept of indicator matrix is proposed to regulate the retrieval subset selection to derive the enhanced ANCC (EANCC) scheme. It is unveiled that the indicator matrix based retrieval subset selection policy can effectively tailor the girth and degree characteristics of the resultant code graph. Since the most harmful short cycles in the network coded cooperation can be completely eliminated, the proposed EANCC approach promises better error performance than the existing ANCC scheme. Numerical results show that it performs 13 dB better than the ANCC scheme at the bit error rate performance of $10^{-5}$ in seven-user network over the Rayleigh block fading channel.

Joint network-channel code optimization for wireless sensor networks

Abstract Optimization of sensor network architecture in order to improve the overall system performance at the end processing station is an important challenge. A lot of architectures have been designed to optimize the bit error rate. Conventionally, this optimization is done by inserting relays between sensors and destination. These relays insert redundant information by mixing the incoming streams from sensor nodes, hence creating parity check information which is very useful to help decode the transmit information from sensors. The goal is to combine network and channel coding to match network on graph to code on graph, and this is called adaptive network coded cooperation (ANCC). Compared to the previous works in the field, we propose a new transmit protocol based on the use of beamforming technique which is very efficient in terms of throughput and is fully compatible with the physical network coding (PNC) principles. Furthermore, we propose a distributed coding scheme where the relay, the destination, and the sensors are all equipped with repeat accumulate (RA) channel code structures. The relay has a special RA structure to suit the need of the PNC multiple access channel.

Generalized Adaptive Network Coding Aided Successive Relaying for Noncoherent Cooperation

A generalized adaptive network coding (GANC) scheme is conceived for a multi-user, multi-relay scenario, where the multiple users transmit independent information streams to a common destination with the aid of multiple relays. The proposed GANC scheme is developed from adaptive network coded cooperation (ANCC), which aims for a high flexibility in order to: 1) allow arbitrary channel coding schemes to serve as the cross-layer network coding regime; 2) provide any arbitrary trade-off between the throughput and reliability by adjusting the ratio of the source nodes and the cooperating relay nodes. Furthermore, we incorporate the proposed GANC scheme in a novel successive relaying aided network (SRAN) in order to recover the typical 50% half-duplex relaying-induced throughput loss. However, in support of the coherent detection, in addition to carrying out all the relaying functions, the relays have to estimate the Source-to-Relay channels, which imposes a substantial extra energy consumption and bit rate reduction owing to the inclusion of pilots. Hence noncoherent detection is employed for eliminating the power-hungry channel estimation. Finally, we intrinsically amalgamate our GANC scheme with the joint network-channel coding (JNCC) concept into a powerful three-stage concatenated architecture relying on iterative detection, which is specifically designed for the destination node (DN). The proposed scheme is also capable of adapting to rapidly time-varying network topologies, while relying on energy-efficient detection.

Feedback-based adaptive network coded cooperation for wireless networks

A novel feedback-based adaptive network coded cooperation (FANCC) scheme is proposed for wireless networks that comprise a number of terminals transmitting data to a common destination. The proposed FANCC exploits network coding and matches code-on-graph with network-on-graph, which is a substantial extension of adaptive network coded cooperation (ANCC). In the relay phase of FANCC, the terminal will be active when its channel fading coefficient magnitude |h| is larger than the threshold T th and the broadcast-packet of one terminal will be possibly selected for check-sum when |h| is less than the threshold R th . In the indication phase, the destination broadcasts above message at cost of 2 bits per terminal. Therefore, distributed fountain codes are generated at the destination. Both achievable rates and outage probabilities are evaluated for FANCC and closed-form expressions are derived when the network size approaches infinity. Moreover, compared with ANCC, analysis results demonstrate that FANCC achieves 1-2 dB performance improvement at the outage probability of 10-6 and 1-2 dB gain at the same achievable rate and the simulation results shows that FANCC has better Frame error ratio (FER) performance. Index Terms--cooperative wireless network, network coding, fountain codes, distributed coding

Adaptive network coded cooperation (ANCC) for wireless relay networks: matching code-on-graph with network-on-graph

We consider user cooperation in a relay network that comprises a large collection of transmitters sending wireless data to a common receiver. A new framework exploiting the network coding technology, referred to as adaptive network coded cooperation (ANCC), is proposed to combat the lossy nature of wireless links and to adapt to the changing network topology. The central idea is to match network-on-graph, i.e. instantaneous network topologies described in graphs, with the well-known class of code-on-graph, i.e. low-density parity-check (LDPC) codes and LDPC-like codes. Both achievable rates and outage probabilities are evaluated for ANCC, and closed-form expressions are derived for the asymptotic case where the network size increases without bound. Compared with the existing schemes, ANCC significantly outperforms repetition-based schemes and performs on par with space-time coded cooperation (STCC), but obviates the need for stringent inter-user synchronization at the bit/baud level.