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This paper considers a multiuser two-way relaying system with time division broadcast (TDBC) protocol, where one multiantenna base station (BS) and one out of N single-antenna mobile stations (MSs) exchange information with the aid of one single-antenna amplify-and-forward (AF) relay. We first propose an optimal joint user-antenna selection scheme, which minimizes the system outage probability. Then...
This paper considers wireless sensor networks with limited bandwidth, where sensors must transmit sensing results that are distorted with noise uncertainty, to the fusion center reliably and efficiently. A class of rate-1 linear complex-field coding (CFC) transmission strategy is developed, to effectively protect the noisy observation of the signals without any bandwidth expansion. Pairwise error...
In heterogeneous networks (HetNet) comprising high power Macro cells and low power small cells, cross-tier interference limits overall capacity with universal frequency reuse. Conventional fractional power control scheme can not effectively deal with interference between Macro cell and small cells. In this paper, we proposed a new uplink power control scheme,which sets the UL SINR target by considering...
Heterogeneous deployment is a promising solution to enhance both system capacity and coverage, where the planned macro cell is overlaid with pico cells. However, higher transmit power of macro eNB (MeNB) results in small coverage for pico cell, which causes insufficient offloading from macro cell to pico cell and inefficient cell splitting gain exploration. Cell range expansion (CRE) is one of alternative...
Femtocells will be widely employed in the next generation wireless networks since they improve indoor capacity and coverage with low cost and low power characteristics. However since macro cells may have to share the same spectrum with femtocells, resource allocation schemes have been a key challenge to manage interference. In this paper, we propose a novel resource allocation scheme based on cognitive...
As for the conventional ground penetrating radar (GPR) system, the detection result is seriously affected by the antenna directionality, the target scattering sections (RCS) and multi-polarization characteristics of electromagnetic wave. The MIMO (Multiple-Input and Multiple-Output) array antenna GPR technology can overcome the influence of RCS, electromagnetic polarization and improve the quality...
Cooperation can significantly improve the diversity order and hence the spectrum sensing accuracy in cognitive radio systems. Since cooperation inevitably introduces communication overhead, question arises as how and how much cooperation should be induced to attain the low-hanging fruits without being excessive and overshadowing the gain. Based on the topology graph, this paper proposes a distributed...
In cognitive radio (CR) networks, the cooperative spectrum sensing can greatly improve the sensing performance. However, several existing cooperative spectrum sensing methods have time asynchronization assumption, which will inevitably bring the waste of waiting time, and will cause many limitations in the practical application. In this paper, we propose an enhanced asynchronous cooperative spectrum...
Coordinated Multi-Point transmission (CoMP) has been recognized as one of the most promising technologies in the 4th generation (4G) cellular systems. It can significantly increase the spectral efficiency by combining the data from different eNBs. However, the benefits come at the cost of the increased feedback overhead. In the downlink frequency division duplex (FDD) systems, UEs need to feedback...
Random beamforming (RBF) can obtain the same capacity scaling compared with the optimal precoding scheme in a sufficient number of users. However, the performance of RBF is decreased severely when with few users. In this letter, we propose a joint RBF and zero-forcing precoding scheme. Based on RBF, the initial scheduling is achieved, then these selected users are requested to feed back quantized...
Cooperative spectrum sensing for cognitive radio is recently being studied to minimize uncertainty in primary user detection. In order to improve the detection probability under a sustainable false alarm probability, a reliable scheme for cooperative spectrum sensing based on double threshold energy detection and Dempster-Shafer (D-S) theory is proposed in this paper. In the algorithm, the double...
The MUSIC based TOA algorithm was briefly introduced. And the resolution analysis of the algorithm was made both in theory and simulation experiments. The function of the resolution ability and the noise threshold of the algorithm were developed. Some conclusions about the choices of the algorithm parameter values were made.
To improve the bandwidth efficiency of the classical orthogonal cooperative transmission scheme while maintaining the cooperative gain, a novel non-orthogonal amplify-and-forward cooperative scheme based on distributed space-time code is proposed. In this scheme, the orthogonal characteristic of Alamouti space-time code is utilized to make cooperative users relay on the shared channel resources so...
Fuzzy logic which processes logical thought based on surrounding fuzzy information, aims to deal with fuzzy information by membership function and serial parallel regulation. By using the concept of membership function in fuzzy mathematics theory to equivalent the interference cancellation factor of each user as a membership function and with the Signal-to-Interference Ratio (SIR) used as a element...
This paper devises a novel group frequency-hopping (FH) scheme for OFDM modulated multiuser system, in order to optimize the resource reuse efficiency and resolve the performance degradation due to the deep fading in the same time. In the OFDM modulated multiuser system, the traditional FH schemes can work in a multipath fading environment and achieve a moderate bit-error-rate (BER). However, when...
This paper studies the relay-assisted inter-vehicular communications (IVCs) with double Rayleigh fading vehicle-to-vehicle links. The OPA (optimal power allocation) solution is derived through maximizing source-to-destination channel capacity assuming amplify-and-forward relaying. The outage performance is discussed and the lower bound on outage probability at medium to high SNR (signal-to-noise ratio)...
This article established a double antennas positioning method and system model. Considering the impact of white Gaussian noise, SNR difference and time difference of arrival of dual-antenna can be calculated at the receiving end to make equations in multi-path fading channel. In the space of two-dimensional the wave source location can be expressed as the function of SNR difference and time difference.
With the introduction of a dither sequence and scaling factors, dithered Tomlinson-Harashima precoding (THP) has shown to outperform conventional spatial THP in multi-user MIMO systems. Through a careful analysis of dithered THP, this paper exhibits that it is not only possible, but also beneficial, to eliminate the dither sequence and develop efficient scale-only THP, and the key is to resolve the...
This paper proposes a method of monitoring and analyzing interharmonics in power system based on modified covariance arithmetic and virtual instrument. The system consists of sensors, signal conditioning circuits, transfer boards, data acquisition (DAQ) and compute, which the parameters of interharmonics are identified by using the modified covariance arithmetic of AR model, Some essential issues,...
This paper proposes a novel construction of analog codes based on nonlinear chaotic dynamical systems in general and the tent map in particular. In light of the importance of the symbolic coding in estimating tent chaos, the proposed construction exploit useful ideas of interleaving and parallel concatenation from classical coding theory to protect symbolic coding and subsequently chaotic states....
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