Distributed scheduling based on polling policy with maximal spatial reuse in multi-hop WMNs

The scheduling algorithm based on the three-way handshaking scheme in IEEE 802.16d-2004 standard has some serious problems because of the complexity of the algorithm and low scheduling efficiency. To enhance the scheduling efficiency and improve the performance of multi-hop wireless mesh networks （WMNs）, one distributed scheduling algorithm that can maximize the spatial and time reuse with an interference-based network model is proposed. Compared to the graph-based network model, the proposed network model can achieve a better throughput performance with maximal spatial reuse. Furthermore, this proposed scheduling algorithm also keeps fairly scheduling to all links, with a priority-based polling policy. Both the theoretical analysis and simulation results show that this proposed distributed scheduling algorithm is simple and efficient.

Efficient delay based scheduling with fairness in multi-hop wireless mesh networks

Some scheduling algorithms have been designed to improve the performance of multi-hop wireless mesh networks （WMNs） recently. However the end-to-end delay is seldom considered as the complexity of multi-hop topology and open wireless shared channel. This article proposes an efficient delay based scheduling algorithm with the concept of buffer-data- hops. Considering the demand satisfaction factor（DSF）, the proposed algorithm can also achieve a good fairness performance. Moreover, with the interference-based network model, the scheduling algorithm can maximize the spatial reuse, compared to those graph-based scheduling algorithms. Detailed theoretical analysis shows that the algorithm can minimize the end-to-end delay and make a fair scheduling to all the links.

Concurrent Transmission with Minimal SR-Pair Interference in WiMAX Mesh Networks

Performance of wireless mesh networks can be greatly improved by spatial reuse （SR）, therefore, lots of algorithms have been proposed to maximize the number of concurrent transmis- sions. However, most methods only considered the interference brought by the sender nodes. In this paper, we study the interfer- ence model in WiMAX mesh networks and propose a minimal SR-pair interference model to perform concurrent transmissions in both uplink and downlink directions. Simulation results show that our model is more efficient and stable, i.e., it increases the number of concurrent transmissions and its performance is constant and independent of transmission directions.

A Dedicated MAC Protocol Package for Real-Time Ocean Current Field Estimation Using Distributed Underwater Acoustic Sensor Networks

Distributed underwater acoustic sensor networks(UASNs)are envisioned in real-time ocean current velocity estimation.However,UASNs at present are still dominated by post-processing partially due to the complexity of on-line detection for travel times and lack of dedicated medium access control(MAC)protocols.In this study,we propose a dedicated MAC protocol package for real-time ocean current velocity estimation using distributed UASNs.First,we introduce the process and requirements of ocean current velocity estimation.Then,we present a series of spatial reuse time division multiple access(TDMA)protocols for each phase of real-time ocean current field estimation using distributed UASNs,followed by numerical analysis.We divide UASNs into two categories according to their computing ability:feature-complete and feature-incomplete systems.The feature-complete systems that have abundant computing ability carry out the presented MAC protocol package in three phases,whereas the feature-incomplete ones do not have enough computing ability and the presented MAC protocol package is reduced to two phases plus an additional downloading phase.Numerical analysis shows that feature-complete systems using mini-slot TDMA have the best real-time performance,in comparison with feature-incomplete systems and other feature-complete counterparts.Feature-incomplete systems are more energy-saving than feature-complete ones,owing to the absence of in-network data exchange.