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Multiple Input Multiple Output (MIMO) systems use multiple transmit and receive antennas to achieve higher data rates by transmitting multiple independent data systems. Transmission errors can be reduced by using Hybrid Automatic Repeat request (HARQ) combining techniques with MIMO systems. We propose two novel MIMO HARQ combining methods which are based on using pre-combining only and a joint post...
In this paper, mobile WiMAX trials are analysed to investigate the vehicular down-link performance for a number of on-car antenna configurations. The directionality and optimum polarization of the vehicular antennas are shown to improve both the range and throughput of the system. These improvements are attributed to the additional directive gain, and the reduced multi-input multi-output spatial correlation...
Interference coordination methods for Evolved-Multimedia Broadcast/Multicast Service (E-MBMS) in Long Term Evolution Advanced (LTE-A) are presented. In this paper, OFDM/OFDMA signals based on LTE parameters are combined with MIMO, Turbo codes and signal space diversity methods. Different interference coordination techniques, such as, MIMO coordination, Fixed Relay stations and adaptive frequency reuse...
Cooperative MIMO (Multiple Input Multiple Output) allows multiple nodes to emulate antenna arrays and transmit or receive cooperatively. This has the ability to increase the capacity for future wireless communication systems and it is particularly suited for Ad Hoc networks. In this study, based on our analysis of the Shannon capacity limit of cooperative MIMO transmission, we have derived an optimal...
This paper presents a pipelined MIMO detector designed for 4×4 16-QAM spatial multiplexing systems. A modified Dijkstra's algorithm and a pre-calculation technique are proposed to improve the throughput up to 2.6Gb/s, and the Euclidean norm computation is approximated to reduce the chip area without degrading the error-rate performance. The entire detector occupies 1.56mm2 in a 0.18μm CMOS process,...
This paper focuses on maximizing Cognitive radio (CR) system capacity by flexible Multiple input multiple output (MIMO) system, while maintaining the interference to primary user (PU) within a limit. It is proposed that MIMO implemented in CR can not only increase throughput but also avoid interference to PU, so two corresponding multi-user MIMO schemes are given and a parameter called transition...
Future wireless communication systems like 3GPP Long Term Evolution are required to support extreme high speed packet data transmission. Due to the limitation of available spectrum resource, high spectrum efficiency technologies are needed to be explored for different OSI layers. Over last decades, many technologies have been investigated to achieve this target. Multiple-input multiple-output (MIMO)...
Fixed-complexity Sphere Decoder (FSD) is a recently proposed technique for Multiple-Input Multiple-Output (MIMO) detection. It has several outstanding features such as constant throughput and large potential parallelism, which makes it suitable for efficient VLSI implementation. However, to our best knowledge, no VLSI implementation of FSD has been reported in the literature, although some FPGA prototypes...
Codebook design has been investigated extensively over the past few years for quantized precoding in Multiple-Input Multiple-Output (MIMO) communication system. Grassmannian line packing (GLP) codebook is widely used in industry and literature. Traditional GLP codebook can only show good performance in spatial uncorrelated channel. But the practical channel is with varied spatial characteristic. In...
Multi-site MIMO (Multiple Input Multiple Output) is a key technology that will enable next generation cellular networks to achieve high throughput in cell-edge areas. However, a multi-site single-user MIMO system is subject to performance degradation in terms of overall system throughput due to the expense of additional assignments of radio resources to cell edge user equipment. This paper presents...
In this paper, the throughput performance of uplink Base Station (BS) cooperation in a realistic multi-cell MIMO system is evaluated. We choose LTE Release 8 as our baseline, and propose a whole implementation scheme for uplink BS cooperation. First we propose a dynamic cooperative BS selection algorithm, in which each cell-edge user will be assigned a potential cooperative BS by comparing the reception...
In this paper, we have proposed link balancing scheme based on MIMO switching for the high speed wireless access system via dual-hop MIMO relays, and analyzed the capacity of different MIMO transmission mode. From these studies, we can conclude that the relayed MIMO system can support high speed group mobility and the link balancing method is able to enhance the transmission performance.
A new scheduling strategy was proposed for the downlink of MIMO channels with zero-forcing beamforming. As the number of simultaneously supportable users at the same frequency is limited by the number of transmit and receive antennas, the base station may select a subset of users in a cell to serve. Exhaustive search for the optimal user set, however, is computationally prohibitive. With revision...
This paper proposes a new wireless scheduling methodology which takes advantage of future predictions of data rate for the several users competing for physical access. Based on a system which allows low-cost 3D mapping of an environment in real-time, the predictions are obtained via either low-resolution path-loss prediction given the physical structure of the surroundings or by reference to data...
This paper developed a framework to analyze the performance gain in multiple-input multiple-output (MIMO) systems together with cognitive radio (CR) interference communication systems based on average channel state information (CSI). Because of interference between the cognitive user and the licensed user, the cognitive user must optimize its power to ensure the licensed user's transmission stability...
In this paper, we proposed a system that combines AMC and MIMO schemes. While conventional AMC system changes only the coding rate and modulation, the proposed AdaptiveMCM system also selects the MIMO scheme (diversity, multiplexing) according to channel condition. Furthermore, by applying pre-coding and antenna subset-selection we not only produce optimal performance but also increase the data rate...
The MIMO-OFDM Adaptive MCM System changes MIMO scheme, channel coding rate, and modulation scheme, adaptively, according to the channel conditions. And the addition of Pre-coding and Antenna Subset Selection assures a better performance and higher data rate. The MIMO-OFDM Adaptive MCM System achieves a better average throughput performance than a Non Adaptive-MCM system; as SNR increases, the throughput...
Smart Antenna Systems use the additional degrees of freedom offered by their multiple antennas to exploit, among other things, multipath in the propagation environment. Therefore, by construction, antenna design of smart antenna systems cannot be assessed by simple performance metrics such as gain, polarization and efficiency alone. At a minimum, performance has to be considered in the context of...
The current literature lacks the VLSI realization of high-order multiple-input-multiple-output (MIMO) detectors in the complex domain, which finds applications in advanced wireless standards such as WiMAX and Long Term Evolution (LTE) systems. In this paper, a novel modified complex K-Best algorithm and its VLSI implementation for a 4 × 4, 64QAM complex MIMO detector are proposed. The main contributions...
In this paper, measured data is presented comparing the data throughput performance of an 802.1 In network with two different configurations. Configuration 1 uses base antennas configured for spatial diversity (three separate dipoles). Configuration 2 uses base antennas configured for pattern diversity (single isolated mode antenna structure). The measurements were performed in a typical office environment...
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