This paper addresses an unfairness problem that exists among vehicles of distinct velocities in IEEE 802.11p based vehicle-to-infrastructure (V2I) networks used for drive-thru Internet applications. The standard IEEE ...This paper addresses an unfairness problem that exists among vehicles of distinct velocities in IEEE 802.11p based vehicle-to-infrastructure (V2I) networks used for drive-thru Internet applications. The standard IEEE 802.11p does not take into account, the residence time of vehicles within the coverage of each road side unit (RSU), for granting channel access. Due to this, a vehicle moving with higher velocity has less chance to communicate with the RSU, as compared to vehicles with lower velocity, due to its shorter residence time in the coverage area of RSU. Accordingly, the data transfer performance of a higher velocity vehicle gets degraded significantly, as compared to that of the vehicle with lower velocity, resulting in unfairness among them. In this paper, our aim is to resolve this unfairness problem by assigning the transmission opportunity (TXOP) limits to vehicles according to their mean velocities. Using an analytical model, we prove that tuning TXOP limit proportional to mean velocity can ensure fairness among vehicles belonging to distinct classes of mean velocities, in the sense of equal chance of communicating with RSU. Analytical results are validated using extensive simulations.展开更多
The rapid development of Wireless Local Area Network (WLAN) has not yet broken the bottleneck that the low transmission speed hinders the further development of WLAN. Now, some key technologies for next generation mob...The rapid development of Wireless Local Area Network (WLAN) has not yet broken the bottleneck that the low transmission speed hinders the further development of WLAN. Now, some key technologies for next generation mobile communications can solve the problem by supporting high-speed transmission and ensuring reliable performance. IEEE 802.11n has made general amendment to 802.11. Based on IEEE 802.11n, the transmission speed can be doubled by the application of Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) technologies on the physical layer. In addition, the enhanced Medium Access Control (MAC) system performance, optimized data frame and improved network throughput can all be achieved by the adoption of frame convergence, Transmission Opportunity (TXOP) and block-acknowledge technologies on the MAC layer. A new error correction method, called Low Density Parity Check Code (LDPC), can also be adopted for the receiver to enjoy low Bit Error Ratio (BER) with low S/N, thus improving signal coverage.展开更多
文摘This paper addresses an unfairness problem that exists among vehicles of distinct velocities in IEEE 802.11p based vehicle-to-infrastructure (V2I) networks used for drive-thru Internet applications. The standard IEEE 802.11p does not take into account, the residence time of vehicles within the coverage of each road side unit (RSU), for granting channel access. Due to this, a vehicle moving with higher velocity has less chance to communicate with the RSU, as compared to vehicles with lower velocity, due to its shorter residence time in the coverage area of RSU. Accordingly, the data transfer performance of a higher velocity vehicle gets degraded significantly, as compared to that of the vehicle with lower velocity, resulting in unfairness among them. In this paper, our aim is to resolve this unfairness problem by assigning the transmission opportunity (TXOP) limits to vehicles according to their mean velocities. Using an analytical model, we prove that tuning TXOP limit proportional to mean velocity can ensure fairness among vehicles belonging to distinct classes of mean velocities, in the sense of equal chance of communicating with RSU. Analytical results are validated using extensive simulations.
基金Programs ofNational Natural Science Foundation of China(No. 60372048, No. 60496316)
文摘The rapid development of Wireless Local Area Network (WLAN) has not yet broken the bottleneck that the low transmission speed hinders the further development of WLAN. Now, some key technologies for next generation mobile communications can solve the problem by supporting high-speed transmission and ensuring reliable performance. IEEE 802.11n has made general amendment to 802.11. Based on IEEE 802.11n, the transmission speed can be doubled by the application of Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) technologies on the physical layer. In addition, the enhanced Medium Access Control (MAC) system performance, optimized data frame and improved network throughput can all be achieved by the adoption of frame convergence, Transmission Opportunity (TXOP) and block-acknowledge technologies on the MAC layer. A new error correction method, called Low Density Parity Check Code (LDPC), can also be adopted for the receiver to enjoy low Bit Error Ratio (BER) with low S/N, thus improving signal coverage.
