分析对比了多种地理空间定位方法，归纳了各种不同尺度下定位的特点，以及定位方法的实现过程，从IEEE802.11无线局域网技术的 MAC 协议出发，提出了基于无线局域网 IEEE802.11技术的地理空间定位方法，实现的技术流程，并分析了其发展...分析对比了多种地理空间定位方法，归纳了各种不同尺度下定位的特点，以及定位方法的实现过程，从IEEE802.11无线局域网技术的 MAC 协议出发，提出了基于无线局域网 IEEE802.11技术的地理空间定位方法，实现的技术流程，并分析了其发展趋势。利用 MAC 的帧头和帧体都可以实现定位功能，利用 MAC 帧头的定位可以适用于计算能力较强的移动台上，而利用帧体的定位，由于只需解析内容不需要查询计算，所以能够用于手机等移动对象。使用无线局域网可以实现定位平台，同时又能实现无线接入的通信功能，所以大大降低了总的建设成本，因此具有很大的现实意义。展开更多
When there are bigger obstacles in the indoor environment such as elevator, the radio waves basically can not penetrate it. The contribution of received signal strength by transmission and reflection will be greatly r...When there are bigger obstacles in the indoor environment such as elevator, the radio waves basically can not penetrate it. The contribution of received signal strength by transmission and reflection will be greatly reduced, and most of the time, the radio waves will reach the user by bypass diffraction. Therefore, the traditional path loss model is no longer applicable, and the improved model should be proposed. In this paper, we firstly proposed an indoor radio propagation model based on dominant path in which the received signal strength has nothing to do with the direct distance between user and access point, but is related to the length of dominant path. Then on the basis of dominant path model, the NLOS influence is considered in order to further improve the accuracy of dominant path model. Experimental results demonstrated that the proposed dominant path model can improve the accuracy of traditional path loss model remarkably.展开更多
In this paper, an improved analytical model for IEEE 802.11 distributed coordination function (DCF) under finite load is proposed by closely following the specifications given in IEEE 802.11 standard. The model is inv...In this paper, an improved analytical model for IEEE 802.11 distributed coordination function (DCF) under finite load is proposed by closely following the specifications given in IEEE 802.11 standard. The model is investigated in terms of channel throughput under perfect and slow Rayleigh fading channels. It is shown that the proposed model gives better insight into the operation of DCF.展开更多
文摘分析对比了多种地理空间定位方法，归纳了各种不同尺度下定位的特点，以及定位方法的实现过程，从IEEE802.11无线局域网技术的 MAC 协议出发，提出了基于无线局域网 IEEE802.11技术的地理空间定位方法，实现的技术流程，并分析了其发展趋势。利用 MAC 的帧头和帧体都可以实现定位功能，利用 MAC 帧头的定位可以适用于计算能力较强的移动台上，而利用帧体的定位，由于只需解析内容不需要查询计算，所以能够用于手机等移动对象。使用无线局域网可以实现定位平台，同时又能实现无线接入的通信功能，所以大大降低了总的建设成本，因此具有很大的现实意义。
文摘When there are bigger obstacles in the indoor environment such as elevator, the radio waves basically can not penetrate it. The contribution of received signal strength by transmission and reflection will be greatly reduced, and most of the time, the radio waves will reach the user by bypass diffraction. Therefore, the traditional path loss model is no longer applicable, and the improved model should be proposed. In this paper, we firstly proposed an indoor radio propagation model based on dominant path in which the received signal strength has nothing to do with the direct distance between user and access point, but is related to the length of dominant path. Then on the basis of dominant path model, the NLOS influence is considered in order to further improve the accuracy of dominant path model. Experimental results demonstrated that the proposed dominant path model can improve the accuracy of traditional path loss model remarkably.
文摘In this paper, an improved analytical model for IEEE 802.11 distributed coordination function (DCF) under finite load is proposed by closely following the specifications given in IEEE 802.11 standard. The model is investigated in terms of channel throughput under perfect and slow Rayleigh fading channels. It is shown that the proposed model gives better insight into the operation of DCF.
