Ad hoc网络是一种无中心的自组织网络,由于用户能量受限当信噪比较低时有效用户识别的可靠性和信道安全性下降。该文针对这个问题提出一种联合有效用户识别与信道安全编译码方法。将发送用户的正交地址码与接收用户的伪随机地址码异或...Ad hoc网络是一种无中心的自组织网络,由于用户能量受限当信噪比较低时有效用户识别的可靠性和信道安全性下降。该文针对这个问题提出一种联合有效用户识别与信道安全编译码方法。将发送用户的正交地址码与接收用户的伪随机地址码异或产生基于发送用户与接收用户的有效用户识别码。为提高信道安全性以信道安全码作为密钥加密有效用户识别码得到正交随机安全序列。为实现扩频并提高传输效率将发送数据以6 bit信息作为一个符号进行分组,将每个符号与一个正交随机安全序列对应。接收用户采用基于子空间的方法处理接收信号,通过建立判决模型识别有效用户。实验结果表明该方法与已有方法相比,当有效用户识别的漏警概率为10^-3时信噪比增益改善1.6 dB。展开更多
Performance of fixed relays in orthogonal frequency division multiple access （0FDMA） systems, especially the coverage and capacity performance at the cell edge, is evaluated in this paper. Two methods, theoretical a...Performance of fixed relays in orthogonal frequency division multiple access （0FDMA） systems, especially the coverage and capacity performance at the cell edge, is evaluated in this paper. Two methods, theoretical analysis and calculation and Monte Carlo simulation, are used for the evaluations. By theoreti- cal analysis and calculation, frequency efficiency equation of a relay is introduced and numerical results are calculated. Monte Carlo simulation results also verify that the calculation method is reasonable. The evaluation shows that a relay can increase system performance to a certain level if it is designed appropriately, otherwise it will be harmful for the system performance, even to reduce it.展开更多
In Orthogonal Frequency Division Multiple Access (OFDMA) systems, such as Long Term Evolution (LTE) and so on, the resources used by each user are orthogonal, and the OFDMA systems performances are mainly affected by ...In Orthogonal Frequency Division Multiple Access (OFDMA) systems, such as Long Term Evolution (LTE) and so on, the resources used by each user are orthogonal, and the OFDMA systems performances are mainly affected by the inter-cell interference. Therefore, the inter-cell interference mitigation technology becomes a hotspot. The objective of interference mitigation technologies used in OFDMA systems are to increase cell-edge throughput and average cell throughput. In this paper, the Resource Block Planning (BRBP) based scheme is proposed to mitigate the inter-cell interference and improve the cell-edge throughput. Comparison between the simulation results of BRBP and Round Robin (RR) illustrates that the enhanced performance of BRBP.展开更多
The next generation space internet （NGSI） is based on all-IP-based mobile network that merges land-based network, sea-based network, sky-based network, spacebased network, deep space-based network together using exi...The next generation space internet （NGSI） is based on all-IP-based mobile network that merges land-based network, sea-based network, sky-based network, spacebased network, deep space-based network together using existing assess network technologies. There are high signal propagation delays, high error rate, bandwidth variation and time-variety in NGSh In order to adapt to various space communication environment constraints and bandwidth variation, we propose a reduced dimension scalable video coding scheme based on CCSDS IDCS algorithm and quality of service （QoS） control method by cross layer design （CLD）. The experimental result shows that this new method has better performance than that of existing algorithms, and can be adaptive to the bandwidth variation dynamically.展开更多
文摘Performance of fixed relays in orthogonal frequency division multiple access （0FDMA） systems, especially the coverage and capacity performance at the cell edge, is evaluated in this paper. Two methods, theoretical analysis and calculation and Monte Carlo simulation, are used for the evaluations. By theoreti- cal analysis and calculation, frequency efficiency equation of a relay is introduced and numerical results are calculated. Monte Carlo simulation results also verify that the calculation method is reasonable. The evaluation shows that a relay can increase system performance to a certain level if it is designed appropriately, otherwise it will be harmful for the system performance, even to reduce it.
文摘In Orthogonal Frequency Division Multiple Access (OFDMA) systems, such as Long Term Evolution (LTE) and so on, the resources used by each user are orthogonal, and the OFDMA systems performances are mainly affected by the inter-cell interference. Therefore, the inter-cell interference mitigation technology becomes a hotspot. The objective of interference mitigation technologies used in OFDMA systems are to increase cell-edge throughput and average cell throughput. In this paper, the Resource Block Planning (BRBP) based scheme is proposed to mitigate the inter-cell interference and improve the cell-edge throughput. Comparison between the simulation results of BRBP and Round Robin (RR) illustrates that the enhanced performance of BRBP.
基金the National Natural Science Foundation of China (Grant Nos. 60773137 and 60573112)the National 863 Project (Grant No. 2007AA01Z297)the National Foundation (Grant No. 1320061262)
文摘The next generation space internet （NGSI） is based on all-IP-based mobile network that merges land-based network, sea-based network, sky-based network, spacebased network, deep space-based network together using existing assess network technologies. There are high signal propagation delays, high error rate, bandwidth variation and time-variety in NGSh In order to adapt to various space communication environment constraints and bandwidth variation, we propose a reduced dimension scalable video coding scheme based on CCSDS IDCS algorithm and quality of service （QoS） control method by cross layer design （CLD）. The experimental result shows that this new method has better performance than that of existing algorithms, and can be adaptive to the bandwidth variation dynamically.
