Longye Wang

Simple Adaptive Single Differential Coherence Detection of BPSK Signals in IEEE 802.15.4 Wireless Sensor Networks

In this paper, we propose an adaptive single differential coherent detection (SDCD) scheme for the binary phase shift keying (BPSK) signals in IEEE 802.15.4 Wireless Sensor Networks (WSNs). In particular, the residual carrier frequency offset effect (CFOE) for differential detection is adaptively estimated, with only linear operation, according to the changing channel conditions. It was found that the carrier frequency offset (CFO) and chip signal-to-noise ratio (SNR) conditions do not need a priori knowledge. This partly benefits from that the combination of the trigonometric approximation sin−1(x)≈x and a useful assumption, namely, the asymptotic or high chip SNR, is considered for simplification of the full estimation scheme. Simulation results demonstrate that the proposed algorithm can achieve an accurate estimation and the detection performance can completely meet the requirement of the IEEE 802.15.4 standard, although with a little loss of reliability and robustness as compared with the conventional optimal single-symbol detector.

Families of asymmetric sequence pair set with zero-correlation zone via interleaved technique

An asymmetric zero-correlation zone (A-ZCZ) sequence pair set is a ZCZ sequence pair set consisting of multiple ZCZ sequence pair subsets. Two arbitrary sequence pairs which belong to different subsets should have a large zero cross-correlation zone (ZCCZ) in the A-ZCZ sequence pair set. Additionally, each subset is a typical ZCZ sequence pair set. The proposed A-ZCZ sequence pair sets can be generated based on interleaved technique from perfect sequence or perfect sequence pair of length P = Nmk with N ≥ 1, m ≥ 1, k > 1. The new A-ZCZ sequence pair sets are applied to quasi-synchronous code-division multiple-access (QS-CDMA) systems and it can hypothetically achieve larger ZCCZ than typical ZCZ sequence pair sets, as well as eliminating both multiple access and multipath interference in the QS-CDMA system.

New families of asymmetric zero-correlation zone sequence sets based on interleaved perfect sequence

A zero-correlation zone (ZCZ) sequence set consisting of multiple ZCZ sequence subsets is said to be an asymmetric ZCZ (A-ZCZ) sequence set if and only if the cross-correlation function (CCF) between two arbitrary sequence which belong to different subsets has quite a large zero-cross-correlation zone (ZCCZ). In such an A-ZCZ sequence set, each subset is a conventional ZCZ sequence set. Our proposed A-ZCZ sequence set can be generated by interleaving any perfect sequence of length P = Nqk with N > 1, q ≥ 1 and k > 1. It is optimal or quasi-optimal conventional ZCZ sequence set if q = 1. The proposed A-ZCZ sequence set are applied to quasi-synchronous code-division multiple-access (QS-CDMA) systems and it can hypothetically achieve larger ZCZ than conventional ZCZ sequence set, as well as eliminating both multiple access and multipath interference in the QS-CDMA system.

Secure Interdependent Networks for Peer-to-Peer and Online Social Network

Peer-to-peer (P2P) systems and online social network (OSN) both have achieved tremendous success. Recent studies suggest that the cooperation of P2P and OSN can achieve better efficiency and security. Unfortunately, novel security problems are emerging as the mutual cooperation and dependence contributes to forming the interdependent networks which are more vulnerable for malicious attack as well as rumor propagation. In this paper, we examined the security environment for P2P and OSN, respectively, and analyzed the security problem derived from the cooperation and interdependence of two networks. The spreader-ignorant-recaller-stifler (SICR) is leveraged to model the rumor spreading in the interdependent networks. In order to enhance the security, we proposed two security schemes named authentication intervening and splitting target and their performance summaries indicate to be effective, simple, and potentially transformative way to guarantee the security for interdependent networks of P2P and OSN.

Simple and Robust Near-Optimal Single Differential Detection Scheme for IEEE 802.15.4 BPSK Receivers

In this study, the authors propose a simple and robust near-optimal single differential coherent detection scheme for IEEE 802.15.4 binary phase shift keying (BPSK) receivers. The detection process is initiated by a bootstrap processor, which is responsible for estimating and compensating the residual carrier frequency offset effect in the sample from the autocorrelator output. In particular, for this bootstrap processor, a simple estimator with only one addition operation is provided. This low complexity benefits from that the high signal-to-noise ratio and a trigonometric approximation are combined, i.e. sin − 1 ( x ) ≃ x , for simplification of the full estimation scheme. Further, to achieve near optimal performance as well as robustness to carrier frequency offset, the observation space is subdivided into four equi-angular regions to decrease the estimation error introduced by the involved approximation. The proposed method is validated through detailed physical layer (PHY) simulations according to the IEEE 802.15.4 standard. The simulation results demonstrate that, compared with the full estimator, the proposed algorithm can acquire a fairly accurate estimation, with almost no loss of reliability and robustness, whereas complexity reduction is also achieved.

An asymmetric ZCZ sequence set with inter-subset uncorrelated property and flexible ZCZ length

In this paper, we propose a novel method for constructing new uncorrelated asymmetric zero correlation zone (UA-ZCZ) sequence sets by interleaving perfect sequences. As a type of ZCZ sequence set, an A-ZCZ sequence set consists of multiple sequence subsets. Different subsets are correlated in conventional A-ZCZ sequence set but uncorrelated in our scheme. In other words, the cross-correlation function (CCF) between two arbitrary sequences which belong to different subsets has quite a large zero cross-correlation zone (ZCCZ). Analytical results demonstrate that the UA-ZCZ sequence set proposed herein is optimal with respect to the upper bound of ZCZ sequence set. Specifically, our scheme enables the flexible selection of ZCZ length, which makes it extremely valuable for designing spreading sequences for quasi-synchronous code-division multiple-access (QS-CDMA) systems.

Novel IGC codes with inter-subset zero-correlation zone for code division multiple access

With the aid of interleaving operations, a novel construction of inter-group complementary (IGC) codes is proposed based on perfect complementary (PC) codes and orthogonal matrices. The presented IGC codes which consists of multiple groups with multiple subsets and each subset is a Z-complementary codes. For the novel IGC code, its cross-correlation function (CCF) between any two codes of different subsets in the same groups have a wider zero correlation zone (ZCZ) than that of any two codes in the same subset and its CCF between any two codes of different groups are zeros everywhere. IGC codes based code division multiple access (CDMA) systems may perform better on bit error rates than conventional codes based traditional interference-limited CDMA systems. Moreover, the new IGC codes may work well in both synchronous and asynchronous operational modes.

5G security architecture and light weight security authentication

The concept of future 5G (the 5th generation of mobile networks) widely spreads in industry, but the related standards are still unclear. The definition of 5G is to provide adequate RF coverage, more bits/Hz and to interconnect all wireless heterogeneous networks to provide seamless, consistent telecom experience to the user. In this paper we have surveyed 5G network architecture and proposed a multi-tier security architecture and a lightweight authentication measure for 5G. The proposed scheme aims at achieving fast authentication and minimizing the packet transmission overhead without compromising the security requirements.

A Novel Construction of Asymmetric Sequence Pairs Set with Zero-Correlation Zone

An asymmetric zero-correlation zone (A-ZCZ) sequence pairs set is a zero-correlation zone (ZCZ) pairs set consisting of multiple ZCZ sequence pairs subsets, where two arbitrary sequence pairs which belong to different subsets should have a large zero cross-correlation zone (ZCCZ). Additionally, each subset is a typical ZCZ sequence pairs set. The new proposed A-ZCZ sequence pairs sets can be generated based on interleaved technique and perfect sequence pairs of length \(P= Nmk\) with \(N>1\), \(m\ge 1\), \(k>1\). The proposed A-ZCZ sequence pairs sets are applied to quasi-synchronous code-division multiple-access (QS-CDMA) systems and it can hypothetically achieve larger ZCCZ than typical ZCZ sequence pairs set, as well as eliminating both multiple access and multipath interference in the QS-CDMA system.