Guang-xin Yue

Adaptive radio resource allocation for multiple traffic OFDMA broadband wireless access system

In this article, an adaptive radio resource allocation algorithm applied to multiple traffic orthogonal frequency division multiple access (OFDMA) system is proposed, which distributes subcarriers and bits among users according to their different quality of service requirements and traffic type. By classifying and prioritizing the users based on their traffic characteristic and ensuring resource for higher priority users, the new scheme decreases tremendously the outage probability of the users requiring a real-time transmission without impact on the spectrum efficiency of system, as well as the outage probability of data users is not increased compared with the radio resource allocation methods published.

Routing Protocol with Optimal Location of Aggregation Point in Wireless Sensor Networks

Abstract A wireless sensor network is typically composed of hundreds, even thousands of tiny sensors used to monitor physical phenomena. As data collected by the sensors are often redundant, data aggregation is important for conserving energy. In this paper, we present a new routing protocol with optimal data aggregation. This routing protocol has good performance due-to its optimal selection of aggregation point locations. This paper details the optimal selection of aggregation point locations.

Joint Downlink Scheduling and Radio Resource Allocation for User-Individual QoS in Adaptive OFDMA Wireless Communication Systems

Abstract This paper proposes and analyzes a downlink multi-carrier proportional fair scheduler and an adaptive radio resource allocation algorithm combining the scheduler. This scheduler and algorithm are suitable for orthogonal frequency division multiple access wireless communication systems supporting multiple quality of service classes. Our results demonstrate that the scheduler and algorithm provide user-explicit fairness with user-individual quality of service guarantees. but the joint scheme achieves a higher sum-rate capacity with flexible parameter settings compared with the multi-carrier proportional fair scheduler.

Optimal power allocation to minimize SER for multinode amplify-and-forward cooperative communication systems

An optimal power allocation (OPA) method with mean channel gains is proposed for a multinode amplify-and-forward cooperative communication system. By making use of M-PSK modulation, a closed-form symbol-error-rate (SER) formulation and corresponding upper bound are first derived. Subsequently the OPA method is utilized to minimize the SER. Comparison of the SER of the proposed OPA method with that of the equal power allocation (EPA) method, shows that the SER of both methods, which is approximately optimal performance, is almost the same when relays are near the source. OPA outperforms the EPA when the relays are near the middle between the source and destination or near the destination. The proposed OPA method depends only on the ratio of mean channel gains of the source-to-relay to those of the relay-to-destination. Extensive simulations are performed to validate the theoretical results.

An Energy-Aware Geographical Forwarding Protocol Utilizing Adaptive Sleeping in Wireless Sensor Networks

This paper proposes a novel energy-aware geographical forwarding protocol utilizing adaptive sleeping, in which each node selects its relay based on a new criterion that is based on its residual energy reserves and its geographical location to guarantee energy efficiency. In addition, this paper presents an adaptive sleep mechanism fully integrated into the new relay criterion, in which each node sleeps for a variable duration based on its residual energy reserves. Simulation results show that the proposed protocol significantly reduces the energy consumption of the network and improves its balance, especially when on heavy traffic load in dense networks. Our protocol is 20 times better in balancing the energy consumption compared with geographical random forwarding protocol.

A cross-layer scheme for medium access control with QoS guaranteeing for Ad hoc networks

Ample medium access control (MAC) protocols for Ad hoc networks have been proposed. However, most of them do not take into account the interactions between the physical (PHY) layer and the MAC layers. Therefore, their efficiency and feasibility are greatly limited. In this article, we present a novel MAC protocol for Ad hoc networks according to the idea of cross-layer design. The proposed protocol combines an MAC protocol termed dual busy tone multiple access (DBTMA) with Orthogonal frequency division multiplexing (OFDM) system in IEEE 802.11a standard. The analysis showed that the proposed protocol provides higher throughput and is more flexible than previous MAC protocols. In addition, it can provide Quality of Service(QoS) guarantee to the packets with different delay requirements in the presence of hidden terminals.

Reduce the decoding complexity: segment linear network coding

Abstract The throughput gain obtained by linear network coding (LNC) grows as the generation size increases, while the decoding complexity also grows exponentially. High decoding complexity makes the decoder to be the bottleneck for high speed and large data transmissions. In order to reduce the decoding complexity of network coding, a segment linear network coding (SLNC) scheme is proposed. SLNC provides a general coding structure for the generation-based network coding. By dividing a generation into several segments and restraining the coding coefficients of the symbols within the same segment, SLNC splits a high-rank matrix inversion into several low-rank matrix inversions, therefore reduces the decoding complexity dramatically. In addition, two coefficient selection strategies are proposed for both centrally controlled networks and distributed networks respectively. The theoretical analysis and simulation results prove that SLNC achieves a fairly low decoding complexity at a cost of rarely few extra transmissions.

Asymptotic analysis for transmission capacity of wireless Ad-hoc networks

Abstract This article puts forward a new solution to the bound of the outage probability and transmission capacity of Ad-hoc networks. For the proofs of the upper and lower bounds are too complex, a much easier way is introduced to get the same results, and by using Taylor series, the asymptotic bound is derived. By comparing with the simulation results, we found that the asymptotic bound is sufficient accurate when the network parameters are selected properly, and is tighter than the upper and lower bounds.

Dynamic subcarrier and power allocation based on cooperative game theory in symmetric cooperative OFDMA networks

Abstract In order to improve the efficiency and fairness of radio resource utilization, a scheme of dynamic cooperative subcarrier and power allocation based on Nash bargaining solution (NBS-DCSPA) is proposed in the uplink of a three-node symmetric cooperative orthogonal frequency division multiple access (OFDMA) system. In the proposed NBS-DCSPA scheme, resource allocation problem is formulated as a two-person subcarrier and power allocation bargaining game (SPABG) to maximize the system utility, under the constraints of each users maximal power and minimal rate, while considering the fairness between the two users. Firstly, the equivalent direct channel gain of the relay link is introduced to decide the transmission mode of each subcarrier. Then, all subcarriers can be dynamically allocated to the two users in terms of their selected transmission mode. After that, the adaptive power allocation scheme combined with dynamic subcarrier allocation is optimized according to NBS. Finally, computer simulation is conducted to show the efficiency and fairness performance of the proposed NBS-DCSPA scheme.

A practical physical network coding scheme over hybrid field

Abstract Physical layer network coding (PNC) exploits the broadcast nature of wireless channels to obtain transmission efficiency gains over traditional network coding schemes. Nevertheless, most PNC schemes are proposed for the two-way relay network where a terminal node is not only a source but also a destination. This paper proposes a joint network coding and modulation (JNCM) scheme under a more general one-way relay network. The JNCM scheme is operated over hybrid field. It is able to adjust its transmission rate according to the channel condition, and enables a reliable transmission of different throughput under different signal-to-noise ratio (SNR). The proposed scheme achieves a better transmission efficiency than the PNC scheme based on the structure codes and a better symbol error rate (SER) performance than the complex field network coding. The excellent performances of JNCM are proved by our simulation results.