A new approach, named TCP-I2NC, is proposed to improve the interaction between network coding and TCP and to maximize the network utility in interference-free multi-radio multi-channel wireless mesh networks. It is gr...A new approach, named TCP-I2NC, is proposed to improve the interaction between network coding and TCP and to maximize the network utility in interference-free multi-radio multi-channel wireless mesh networks. It is grounded on a Network Utility Maxmization (NUM) formulation which can be decomposed into a rate control problem and a packet scheduling problem. The solutions to these two problems perform resource allocation among different flows. Simulations demonstrate that TCP-I2NC results in a significant throughput gain and a small delay jitter. Network resource is fairly allocated via the solution to the NUM problem and the whole system also runs stably. Moreover, TCP-I2NC is compatible with traditional TCP variants.展开更多
In Wireless Mesh Networks (WMNs),the performance of conventional TCP significantly deteriorates due to the unreliable wireless channel.To enhance TCP performance in WMNs,TCP/LT is proposed in this paper.It introduces ...In Wireless Mesh Networks (WMNs),the performance of conventional TCP significantly deteriorates due to the unreliable wireless channel.To enhance TCP performance in WMNs,TCP/LT is proposed in this paper.It introduces fountain codes into packet reorganization in the protocol stack of mesh gateways and mesh clients.Furthermore,it is compatible with conventional TCP.Regarded as a Performance Enhancement Proxies (PEP),a mesh gateway buffers TCP packets into several blocks.It simultaneously processes them by using fountain encoders and then sends them to mesh clients.Apart from the improvement of the throughput of a unitary TCP flow,the entire network utility maximization can also be ensured by adjusting the scale of coding blocks for each TCP flow adaptively.Simulations show that TCP/LT presents high throughput gains over single TCP in lossy links of WMNs while preserving the fairness for multiple TCPs.As losses increase,the transmission delay of TCP/LT experiences a slow linear growth in contrast to the exponential growth of TCP.展开更多
A novel backoff algorithm in CSMA/CA-based medium access control (MAC) protocols for clustered sensor networks was proposed. The algorithm requires that all sensor nodes have the same value of contention window (CW) i...A novel backoff algorithm in CSMA/CA-based medium access control (MAC) protocols for clustered sensor networks was proposed. The algorithm requires that all sensor nodes have the same value of contention window (CW) in a cluster, which is revealed by formulating resource allocation as a network utility maximization problem. Then, by maximizing the total network utility with constrains of minimizing collision probability, the optimal value of CW (Wopt) can be computed according to the number of sensor nodes. The new backoff algorithm uses the common optimal value Wopt and leads to fewer collisions than binary exponential backoff algorithm. The simulation results show that the proposed algorithm outperforms standard 802.11 DCF and S-MAC in average collision times, packet delay, total energy consumption, and system throughput.展开更多
基金This work was supported by the State Key Program of Na- tional Nature Science Foundation of China under Grants No. U0835003, No. 60872087.
文摘A new approach, named TCP-I2NC, is proposed to improve the interaction between network coding and TCP and to maximize the network utility in interference-free multi-radio multi-channel wireless mesh networks. It is grounded on a Network Utility Maxmization (NUM) formulation which can be decomposed into a rate control problem and a packet scheduling problem. The solutions to these two problems perform resource allocation among different flows. Simulations demonstrate that TCP-I2NC results in a significant throughput gain and a small delay jitter. Network resource is fairly allocated via the solution to the NUM problem and the whole system also runs stably. Moreover, TCP-I2NC is compatible with traditional TCP variants.
基金supported by the State Key Program of National Nature Science Foundation of China under Grants No.U0835003,No.60872087
文摘In Wireless Mesh Networks (WMNs),the performance of conventional TCP significantly deteriorates due to the unreliable wireless channel.To enhance TCP performance in WMNs,TCP/LT is proposed in this paper.It introduces fountain codes into packet reorganization in the protocol stack of mesh gateways and mesh clients.Furthermore,it is compatible with conventional TCP.Regarded as a Performance Enhancement Proxies (PEP),a mesh gateway buffers TCP packets into several blocks.It simultaneously processes them by using fountain encoders and then sends them to mesh clients.Apart from the improvement of the throughput of a unitary TCP flow,the entire network utility maximization can also be ensured by adjusting the scale of coding blocks for each TCP flow adaptively.Simulations show that TCP/LT presents high throughput gains over single TCP in lossy links of WMNs while preserving the fairness for multiple TCPs.As losses increase,the transmission delay of TCP/LT experiences a slow linear growth in contrast to the exponential growth of TCP.
基金Project(60772088) supported by the National Natural Science Foundation of China
文摘A novel backoff algorithm in CSMA/CA-based medium access control (MAC) protocols for clustered sensor networks was proposed. The algorithm requires that all sensor nodes have the same value of contention window (CW) in a cluster, which is revealed by formulating resource allocation as a network utility maximization problem. Then, by maximizing the total network utility with constrains of minimizing collision probability, the optimal value of CW (Wopt) can be computed according to the number of sensor nodes. The new backoff algorithm uses the common optimal value Wopt and leads to fewer collisions than binary exponential backoff algorithm. The simulation results show that the proposed algorithm outperforms standard 802.11 DCF and S-MAC in average collision times, packet delay, total energy consumption, and system throughput.
