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
In this letter, the physical layer security of hybrid automatic repeat request with chase combining(HARQ-CC) scheme is investigated from the viewpoint of information theory. Different from the literature which used Wy...In this letter, the physical layer security of hybrid automatic repeat request with chase combining(HARQ-CC) scheme is investigated from the viewpoint of information theory. Different from the literature which used Wyner code, our analysis focuses on the general scenario without specific code. We firstly obtain the outage probability of both main channel and wiretap channel. Since retransmissions are completely determined by main channel, we then prove that its achievable diversity order equals to maximum transmission number() while this order of wiretap channel is only one. Furthermore, we evaluate the metric of secure gap which demonstrates the difference between main channel and wiretap channel with reliable and secure constraints. As increases, the secure gap decreases monotonously. When is large enough, the security can be guaranteed even if wiretap channel is better than main channel.展开更多
In the field of sequencing of secret number,an important problem is how to establish an efficient and secure protocol for sorting the secret number.As a powerful tool in solving privacy sequencing problems,secure mult...In the field of sequencing of secret number,an important problem is how to establish an efficient and secure protocol for sorting the secret number.As a powerful tool in solving privacy sequencing problems,secure multipart computation is more and more popular in anonymous voting and online auction.In the present study,related secure computation protocol for sequencing problem is not many by far.In order to improve the efficiency and safety,we propose a security sequencing protocol based on homomorphic encryption.We also give analysis of correctness and security to highlight its feasibility.展开更多
To investigate the impact of antenna correlation on secrecy performance in MIMO wiretap channels with Nakagami-m fading, the expressions of secrecy outage probability and positive secrecy probability were derived. Div...To investigate the impact of antenna correlation on secrecy performance in MIMO wiretap channels with Nakagami-m fading, the expressions of secrecy outage probability and positive secrecy probability were derived. Diversity order and array gain were also achieved for further insight. The study was based on the information theory that physical layer security can be guaranteed when the quality of the main channel is higher than that of the eavesdropper's channel. Monte Carlo simulations well validated the numerical results of analytic expressions. It was shown that antenna correlation is detrimental to secrecy performance when average SNR of the main channel is at medium and high level. Interestingly, when average SNR of the main channel reduces to low level, the effect of antenna correlation becomes benefi cial to secrecy performance.展开更多
There is an increasing demand on wireless communications in subway tunnels to provide video surveillance and sensory data for security,maintenance and train control,and to offer various communication or entertainment ...There is an increasing demand on wireless communications in subway tunnels to provide video surveillance and sensory data for security,maintenance and train control,and to offer various communication or entertainment services(e.g.,Internet,etc.) to passengers as well.The wireless channel in tunnels is quite unique due to the confined space and the waveguide effects.Therefore,modeling the radio channel characteristics in tunnels is critically important for communication systems design or optimization.This paper investigates the key radio channel characteristics of a subway tunnel at 2.4 GHz and 5 GHz,such as the path loss,root mean square(RMS) delay spread,channel stationarity,Doppler shift,and channel capacity.The field measurements show that channel characteristics in tunnels are highly location-dependent and there exist abundant components in Doppler shift domain.In the straight section of the subway tunnel,the measured path loss exponents are close to1.6,lower than that in free space.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant No. 61072059
文摘In this letter, the physical layer security of hybrid automatic repeat request with chase combining(HARQ-CC) scheme is investigated from the viewpoint of information theory. Different from the literature which used Wyner code, our analysis focuses on the general scenario without specific code. We firstly obtain the outage probability of both main channel and wiretap channel. Since retransmissions are completely determined by main channel, we then prove that its achievable diversity order equals to maximum transmission number() while this order of wiretap channel is only one. Furthermore, we evaluate the metric of secure gap which demonstrates the difference between main channel and wiretap channel with reliable and secure constraints. As increases, the secure gap decreases monotonously. When is large enough, the security can be guaranteed even if wiretap channel is better than main channel.
基金supported by the National Natural Science Foundation of China under Grant No.51307004
文摘In the field of sequencing of secret number,an important problem is how to establish an efficient and secure protocol for sorting the secret number.As a powerful tool in solving privacy sequencing problems,secure multipart computation is more and more popular in anonymous voting and online auction.In the present study,related secure computation protocol for sequencing problem is not many by far.In order to improve the efficiency and safety,we propose a security sequencing protocol based on homomorphic encryption.We also give analysis of correctness and security to highlight its feasibility.
文摘To investigate the impact of antenna correlation on secrecy performance in MIMO wiretap channels with Nakagami-m fading, the expressions of secrecy outage probability and positive secrecy probability were derived. Diversity order and array gain were also achieved for further insight. The study was based on the information theory that physical layer security can be guaranteed when the quality of the main channel is higher than that of the eavesdropper's channel. Monte Carlo simulations well validated the numerical results of analytic expressions. It was shown that antenna correlation is detrimental to secrecy performance when average SNR of the main channel is at medium and high level. Interestingly, when average SNR of the main channel reduces to low level, the effect of antenna correlation becomes benefi cial to secrecy performance.
基金supported in part by the NSFC project under grant No.61132003the Fundamental Research Funds for the Central Universities(2013JBZ002)the Ph.D.Program Foundation of Ministry of Education of China under grant No.20120009130002
文摘There is an increasing demand on wireless communications in subway tunnels to provide video surveillance and sensory data for security,maintenance and train control,and to offer various communication or entertainment services(e.g.,Internet,etc.) to passengers as well.The wireless channel in tunnels is quite unique due to the confined space and the waveguide effects.Therefore,modeling the radio channel characteristics in tunnels is critically important for communication systems design or optimization.This paper investigates the key radio channel characteristics of a subway tunnel at 2.4 GHz and 5 GHz,such as the path loss,root mean square(RMS) delay spread,channel stationarity,Doppler shift,and channel capacity.The field measurements show that channel characteristics in tunnels are highly location-dependent and there exist abundant components in Doppler shift domain.In the straight section of the subway tunnel,the measured path loss exponents are close to1.6,lower than that in free space.
