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A novel omnidirectional microstrip patch antenna is proposed for wireless communication system in this paper. The antenna presented input impedance bandwidth for S11<-10dB reaches 8.6% (2120MHz ∼ 2310MHz) at center frequency 2200MHz. The antenna has omnidirectional radiation pattern in H-plane having its radiation pattern very similar to an electric monopole. The simulated maximum gain reaches...
As the RRM (Radio Resource Management) conformance testing has become a necessary phase during the development process, the LTE wireless terminal tester must be designed. For this purpose, a new testing method is designed by implementing testing and test control notation version 3 (TTCN-3) test suit in the case of cell reselection. Furthermore, the test suit is executed on the TTworkbench platform...
Delay and reliability sensitive safety messages and throughput sensitive non-safety messages are transmitted in VANETs. Throughput and delay are always opposed in wireless networks, so it is necessary to reach the optimum point between these two parameters in many cases. This paper presents an optimization method of the back-off parameters in multi-priority supported multi-channel MAC protocol in...
In this paper, we focus on the resource scheduling of Long Term Evolution — Advanced (LTE-A) with Carrier Aggregation (CA). Application of CA meets the demand of bandwidth in LTE-A by aggregating several discrete carriers together. With different fading characters, the aggregated carriers have different coverage between each other. Considering the backward compatibility, there exist both LTE-A and...
In this paper, we present two improved methods based on the minimize the mean square error (MMSE) to adaptively cancel the correlated and uncorrelated interference signals completely. The two methods include the eigenspace-based (ESB) adaptive interference cancellation method and projection approach (AP) for adaptive interference cancellation method. Computer simulations are provided to evaluate the...
Aimed at the problem that system energy consumption of traditional cooperative multicast is becoming larger with the increase of the number of users, a method of energy efficient relay selection is proposed. By using channel state information (CSI) among users, each user with poor channel condition selected a user, who had the best channel condition with it, as a relay, the selected user had decoded...
A new adaptive subcarrier grouping scheme is proposed to maximize capacity of single-carrier FDMA (SC-FDMA) system. In OFDM system, the SNR of each subcarrier is dependent on the frequency selective channel fading. While in SC-FDMA system, the SNR of each symbol is of the same value. Theoretical analysis shows that the SNR of the received SC-FDMA symbol is dominated by some few deepest fading subcarriers...
In this paper, we analyze the bit error rate (BER) performance of selective decode-and-forward (DF) cooperative communications incorporating space-frequency block coding (SF-BC), bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). For the classical 3-node cooperation model, a tight upper bound of BER for the coded system under Rayleigh fading channels is...
In this paper, we present the end-to-end performance of a dual-hop cooperative system over independent non-identical composite Nakagami-lognormal (NL) fading channels using Mixture Gamma (MG) distribution. Novel closed-form expressions for the Probability density function (PDF) and the Moment-generation function (MGF) of the end-to-end Signal-to-noise ratio (SNR) are derived. Moreover, the average...
As an overlay cognitive radio system, transform domain communication system (TDCS) has been proposed to support multiuser communication with low spectral density by using spectrum bin nulling and frequency domain spreading. It has been shown that TDCS has a low spectrum efficiency compared to other wireless communication systems. To solve this problem, this paper presents a cluster-based TDCS scheme...
Femtocell is a promising technology which can significantly improve the spectrum efficiency and system capacity of wireless cellular network. However, densely and randomly deployed femtocells may experience server inter-femtocell interference due to rough-and-tumble spectrum reuse with unconstrained power. Different from traditional macrocells, there is no central controller available for femtocells...
Spectrum is the most valuable resource in communication system, but unfortunately, so far, a half of the spectrum has been wasted. In this paper, we will see that the negative frequency not only has a physical meaning but also can be used in communication. In fact, the complete description of a frequency signal is a rotating complex-frequency signal, in a complete description, positive and negative...
In this paper, we study the optimal spectrum access in cognitive relay networks where multiple secondary users can access the unutilized idle spectrum of the primary users and conduct bidirectional communication. The spectrum access problem in the considered system model is defined as joint relay selection and discrete power control. Our goal is to maximize network utility function which takes the...
The potential of WPAN — Wireless Personal Network applications is virtually untapped. The low cost and its presence in most mobile devices make Bluetooth technology one logical choice to be explored. Existing models neglect Bluetooth technical communication, FHSS — Frequency-Hopping Spread Spectrum, and part of the challenge of generating efficient Scatternet algorithms is related to its characteristics...
The Multi-Source Relay-Based Cooperative Communication (MRBCC) is widely used to improve the channel reliability. Recently, there are two major Network Coding (NC) methods proposed for MRBCC. One is the Galois Fields NC (GFNC) which implements the NC scheme by randomly choosing encoding vectors from a high order Galois field. The other is the Complex Field NC (CFNC) where the author proposes an approach...
In this paper, we establish a game theoretic framework of the auction based dynamic spectrum access for multitype buyers (i.e., the secondary users that have different risk preferences) in cognitive radio networks where the auction mechanisms of the primary user are parameterized and can be adaptively designed. We design the utility functions of the multitype secondary users. The proposed game is...
Spectrum sensing is a fundamental component in Cognitive Radio networks. Some detection methods for spectrum sensing in IEEE 802.22 Wireless Regional Area Networks (WRAN) were proposed. In this paper, a sensing algorithm of wireless microphone signals based on compressive sensing, Fast Fourier Sampling (FFS), is analyzed and compared with the traditional spectrum sensing algorithms. Although the detection...
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