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Multiple antenna techniques are used to enhance wireless links and therefore have been studied extensively. Many practical systems differ from the ideal schemes discussed in the literature. One example is the lack of precise channel information at the transmitter. We evaluate analytically the performance of a beamforming technique that uses partial channel knowledge. Specifically, we analyze a suboptimal...
Wideband indoor measurements employ a variety of techniques from off the shelf equipment such as network analysers, to custom designed channel sounders. Depending on the channel parameters, different architectures have been used which include single input single output (SISO), single input multiple output (SIMO) and multiple input multiple output (MIMO). This paper compares the different techniques...
Recently, several multi-channel MAC protocols have been proposed for wireless sensor networks (WSNs) to improve network capacity and boost energy efficiency. In addition, cooperative multiple-input multiple-output (MIMO) technique has been shown to be able to significantly enhance the energy efficiency of WSNs if properly configured. However, these two promising techniques have not been jointly utilized...
Receive beamfoming techniques play an important role in MIMO communications systems as means to mitigate interference and enhance the link quality. Multipoint receive beamforming methods are expected to provide additional gains in systems employing advanced coordinated multipoint processing. Due to its importance, receive beamforming has been studied extensively in the literature. The optimal detection...
Space-time block codes (STBC) are widely used to obtain diversity gain in multiple-input multiple-output (MIMO) channel and Turbo codes are used to provide coding gain. So here a turbo-coded STBC concatenated system, which fully exploits the diversity gain and coding gain are studied. Specially we propose an iterative decoding scheme with a soft information processor created in the system to adjust...
Full-duplex relays can provide cost-effective cover-age extension and throughput enhancement. However, the main limiting factor is the resulting self-interference signal which deteriorates the relay performance. In this paper, we propose a novel technique for self-interference suppression in full-duplex Multiple-Input Multiple-Output (MIMO) relays. The relay employs transmit and receive weight filters...
We set up the uplink MIMO channel model between base station (BS) and mobile station (MS). Several parameters have been considered, including the distinguishable paths, the indistinguishable paths, angular spread, antenna polarization, linear receiving antenna array and other factors. Secondly, this paper simulates the space statistical properties of MIMO antenna channel by MATLAB. Analysis results...
IMT-Advanced systems are currently in their evaluation phase. Due to the complexity of all the integrated algorithms and the multidimensional variability of the wireless channels a system evaluation is not easy and only very few large enterprises have the manpower to construct software to simulate all relevant effects. Traditionally the effects of channel and physical layer algorithms have been studied...
TD-LTE as the evolution of TD-SCDMA is designed to support high data rates and reduced radio link delays. To reach these goals, new air interface is specified for TD-LTE. In this paper, the performance of physical uplink and downlink channels are evaluated by means of numerical simulations. Since the deployment of smart antennas is the unique feature of TD-SCDMA, special attentions are paid to the...
This paper concerns delay analysis for Fair Power Allocation Strategy (FPAS) in multi antenna Broadcast Channel (BC). It is assumed the transmitter aims at sending individual information to a large number of single-antenna users (n) through a common wireless channel. Assuming there is a total transmit power constraint, the FPAS attempts to select the maximum number of active users in which each can...
This paper focuses on design, implementation and optimization of digital front end module of Multiple Input Multiple Output (MIMO)-Orthogonal Frequency Division Multiplexing (OFDM) system on FPGA employing Alamouti Technique (Space Time Block coding). MIMO-OFDM can very effectively be used to achieve higher data rates and higher reliability and this is going to be the Key for 4G Technology. MIMO-OFDM...
This paper presents a least square based semi-blind channel estimation using the new orthogonal pilot scheme for multiple-input multiple-output (MIMO) wireless communications. In practice, knowledge of the wireless unknown channel is often estimated by sending known training symbols to the receiver. We determine the optimal training sequence aiming to minimize the mean square error (MSE) of the channel...
4G mobile wireless radio technologies are focused on delivering higher levels of throughput through the use of Multiple Input, Multiple Output (MIMO) technology. MIMO systems use multiple transmit and receive data paths to provide significant increases in data throughput by exploiting the characteristics of the radio channel. Thus, MIMO system performance is directly related to the propagation environment...
As one kind of multiple input multiple output (MIMO) techniques in the 3GPP Long Term Evolution (LTE) and LTE-advanced (LTE-A) systems, eigenvalue based beam-forming (EBB) can maximize the system capacity in single-user scenario. Traditionally, EBB algorithm often takes singular value decomposition (SVD) to the average channel matrix of each resource block (RB) or RB-group. This method is simple but...
The tracking of fading wireless channel is needed in MIMO-OFDM system. Training sequences can be used for synchronization and channel estimation. However, if too much training blocks are used, the efficiency of system will be decreased. A simplified training pattern which can reduce the waste of resources is proposed in this paper. Computer simulations prove that performance of the system with simplified...
A multiple-input multiple-output (MIMO) baseband transceiver for multi-band orthogonal frequency-division multiplexing (MB-OFDM) ultra-wideband (UWB) communications is proposed in the paper. In the transceiver, a spatial multiplexing scheme with four transmit and four receive antennas is utilized to increase spectrum efficiency and achieve 1.92-Gbps data rate. Performance of both the MIMO and single-input...
This paper utilizes an adaptive modulation and coding (AMC) scheme and compares the performance of adaptation between single-user multiple input multiple output (SU-MIMO) and multi-user (MU) MIMO with that of SU-MIMO. In long term evolution (LTE), every UE only needs to feed back SU-MIMO rank 1 channel quality indicator (CQI) which could get feedback overhead and computational complexity reduction...
Multi-user MIMO systems have the potential to combine the high capacity achievable with MIMO processing with the benefits of space-division multiple access. Although recent theoretical results show that the sum capacity grows linearly with the minimum of the number of antennas and users, the sum rate of channel inversion does not due to the large spread in the singular values of the channel matrix...
In this paper, we introduce a full-duplex relay (FDR) based on block diagonalization (BD) and analyze the corresponding sum rate in a multiantenna multiuser relay system. The poposed precoding scheme can suppress the self-interference as well as to support multiple users at the same time slot. Simulation results show that the proposed FDR scheme enhances significantly the sum rate performance compared...
We propose a new framework for MIMO decoding based on a recently developed technique for reliably conveying linear equations over wireless channels. Each transmit antenna sends an independent data stream using the same linear code. As a result, any integer combination of the codewords is itself a codeword. Each receive antenna observes a random complex-valued combination of the codewords according...
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