Jing Yue

Distributed Fountain Codes With Adaptive Unequal Error Protection in Wireless Relay Networks

In wireless relay networks (WRNs), multiple source nodes communicate with a single destination node through a common relay network. Different source nodes may have different error protection or recovery time requirements. In this paper, we focus on unequal error protection (UEP) distributed network coding (DNC) design for WRNs. Specifically, we propose a continuous UEP method based on fountain codes with the objective of satisfying the UEP or unequal recovery time (URT) requirements. Then based upon this UEP method, we develop an adaptive UEP DNC scheme to realize adaptive UEP in WRNs. We analyze the properties of the proposed adaptive UEP DNC scheme and derive the upper and lower bit error rate (BER) bounds for it over Rayleigh fading channels under maximum-likelihood (ML) decoding. Simulation results show that the proposed adaptive UEP DNC scheme has desirable UEP and URT properties. The transmitted data from the source nodes in different protection groups can be recovered successfully under their performance requirements in a shorter time by using the adaptive UEP DNC scheme.

The design of degree distribution for distributed fountain codes in wireless sensor networks

In this paper, we first analyse bit error rate (BER) bounds of the distributed network coding (DNC) scheme based on the Luby-transform (LT) codes, which is a class of fountain codes, for wireless sensor networks (WSNs). Then we investigate the effect from two parameters of the degree distributions, i.e., the degree value and the proportion of odd degree, to the performance of the LT-based DNC scheme. Based on the analysis and investigation results, a degree distribution design criteria is proposed for the DNC scheme based on fountain codes over Rayleigh fading channels. We compare the performance of the DNC scheme based on fountain codes using degree distributions designed in this paper with other schemes given in the literature. The comparison results show that the degree distributions designed by using the proposed criteria have better performance.

Achieving reliable and efficient transmission by using network coding solution in industrial wireless sensor networks

When deploying wireless sensor networks (WSNs) for industrial applications, to provide reliable data transmission as a stringent requirement must be fulfilled. However, due to dynamic industrial environments, interferences and node failures, to achieve this goal faces a number of challenges. Moreover, reliable transmission solution should also be resource efficient, so more wireless sensor nodes can be supported in a network especially when network resources are limited. In this paper, we applied network coding techniques based on a controlled flooding transmission scheme for industrial wireless sensor networks (IWSNs). Network and channel coding are joint designed for data transmission. We analyzed the theoretical performance of the proposed scheme and compared the performance of our method with the original transmission method in terms of reliability and efficiency. Comparison results showed that by using our proposed network coding solution, the reliability gain can be achieved and the network resource efficiency can be improved.

Network coding for reliable downlink transmissions in industrial wireless sensor and actuator networks.

Benefits, such as significant reduction of cost and complexity, brought by wireless communication make wireless networks more and more appealing for industrial applications. However, before wireless systems can be deployed in industrial networks, strict industrial requirements on reliability and timeliness must be fulfilled and thus protocols increasing the performance of wireless communication are needed. Data in industrial systems is typically transmitted in two directions: from sensor nodes to a controller (uplink transmission) and from the controller to actuators (downlink transmission). Several previous studies have looked at possibilities of performance increase in uplink transmissions from the sensors, while not that much work focused on downlink transmissions, which are equally important. Thus, this paper addresses the downlink transmission scenario and presents a new protocol introducing network coding into packet forwarding scheme. Simulation results show that packet reception rate can be increased when network coding is applied.

Performance Analysis of Unequal Error Protection Distributed Network Coding Based on Fountain Codes

In this paper, we propose an unequal error protection (UEP) distributed network coding (DNC) scheme based on fountain codes to provide arbitrary error protection (i.e., infinite protection levels) to all the source nodes in wireless relay networks (WRNs). We derive the upper and lower bit error rate (BER) bounds for the proposed UEP DNC scheme with maximum-likelihood (ML) decoding over Rayleigh fading channels. Numerical results show that the derived analytical bounds are tight and our proposed UEP DNC scheme based on fountain codes has a strong UEP property.

Performance analysis of distributed raptor codes in wireless relay networks

In this paper, we propose a distributed network coding (DNC) scheme based on the Raptor codes for wireless relay networks (WRNs), where a group of source nodes communicate with a single sink through a common relay network in a multi-hop fashion. At the sink, a graph-based Raptor code is formed on the fly. After receiving a sufficient number of encoded packets, the sink begins to decode. The main contributions of this paper are the derivations of upper and lower bit error rate (BER) bounds for the proposed Raptor-based DNC scheme.

Design and performance analysis of network code division multiplexing for wireless sensor networks

In this paper, we investigate the performance of a wireless sensor network, in which multiple groups of source nodes communicate with their respective destination nodes with the help of a common relay network. A network code division multiplexing (NCDM) scheme is proposed to remove the inter-session interference among multiple transmission sessions at each destination. We focus on analyzing the soft processing algorithm of the NCDM scheme. Based on the analysis results, a new code design criteria for the construction of the generator matrix is proposed. Simulation results show that by following the proposed code design criteria, the bit error ratio (BER) performance gap between the scheme we studied and the serial session scheme can be managed effectively. In serial session scheme, source nodes in a number of groups communicate with their respective destinations in a time division manner.

Network Code Division Multiplexing for Wireless Relay Networks

In this paper, we investigate the performance of a wireless relay network with multiple transmission sessions, in which multiple groups of source nodes communicate with their respective destination nodes via a shared wireless relay network. A multiple transmission session model with network code division multiplexing (NCDM) scheme is proposed to remove the inter-session interference at each destination. The fundamental idea of the NCDM scheme takes advantage of the property of G Θ HT = 0 of the low-density generator matrix (LDGM) codes. Based on the analysis of the NCDM scheme, we investigate the relationship among the equivalent received signal vector, the number of sessions and the column weight of the generator matrix. New code design criteria for the construction of the generator matrix is proposed. We further evaluate the multiple transmission session model with the proposed NCDM scheme in terms of throughput and complexity. Our evaluation demonstrates that the proposed scheme not only has a linear computational complexity, but also shows a similar error performance in the AWGN case and a considerable throughput improvement compared with its counterpart, which is referred to as a serial session scheme, where groups of source nodes communicate with their respective destinations in a time division manner.

On estimation of protection parameters for unequal error protection distributed fountain codes in wireless relay networks

In many applications of wireless relay networks (WRNs), such as image and video systems, unequal error protection (UEP) among the transmission data from different source nodes is required. All the source nodes in a WRN with different protection requirements form multiple protection groups. In this paper, we focus on estimating the protection parameter, i.e., the protection weight, for each protection group. We first analyze the bit error rate (BER) upper bound of the UEP distributed fountain codes over Rayleigh fading channels for WRNs. Then based on the analysis results, we derive the approximate expression for the BER upper bound with protection weight as the variable. The derived approximate expression can be used to estimate the protection weights for the protection groups according to their various performance requirements. Finally, examples on the application of the approximate expression in estimating protection weights are given.

Design and performance analysis of distributed network-channel codes for wireless sensor networks

In this paper, we analyse the performance of distributed network-channel coding (DNCC) with multiple destinations executing a code nulling (MDCN) process. By analysing the formulation deduced from DNCC with the MDCN process, we find that some unstable zero elements and additional noise are generated after right multiplying the parity-check matrix. These unstable zero elements and additional noise are the reasons to degrade BER performance in the two groups of source nodes and two destination nodes (TSTD) network model. Theoretical bit error ratio (BER) curves are drawn according to the calculated equivalent received signal-to-noise ratio (SNR). The analysis results are consistent with the theoretical curves. A design principle for the generator matrix of the DNCC scheme is proposed to solve the BER performance degradation problem. Simulation results show that the problem caused by the MDCN process can be managed effectively and the BER performance can be improved significantly by using the proposed design principle.