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Performance gain can be obtained by dynamically reconfiguring the uplink and downlink radio frames in TDD systems. FDD systems can also benefit from the flexibility in the allocation of uplink and downlink resources. The paper proposes a specific implement of flexible duplex based on selection between different designs of radio frames to make the FDD network more adaptive to the real time situation...
Antenna calibration to enhance the channel reciprocity between the uplink and downlink channels is necessary for the practical wireless system operating in the time division duplexing (TDD) mode. This paper investigates on the computation of the antenna calibration coefficients of the cooperative base stations' antennas in the network multiple-input and multiple-output (MIMO) system. An efficient...
This paper investigates the transmission capacity of the secondary network in overlaid ad hoc networks with multi-antenna spatial multiplexing. Based on stochastic geometry tools, we study the effects of the node density and the transmission power of the secondary network on the transmission capacity performance. We derive the optimal node density for the secondary network, and subsequently the optimal...
Coordinated multi-point transmission with limited rate feedback has been paid much attention recently due to its ability to overcome the detrimental propagation conditions. In the limited feedback multi-point transmission, how to allocate the appropriate feedback bits among the users has become a critical issue to be investigated. The existing schemes have not considered the impact of the flexible...
Simulation of wireless communication system is usually divided into system-level and link-level. Link-level simulation is generally used to simulate the point-to-point physical layer technologies with propagation model taken into account, which means it is based on single-cell and single terminal scenario. Multi-cell model is not often studied in link-level mainly due to its high complexity. So we...
In practical use, data traffic has a feature of high-burst in wireless network, which means that the serve request of a user is not continuous. With full buffer traffic model, network operators can give evaluations on the peak data rate and the least data rate of heavy load network. However, rather than the peak data rate and the least data rate, what attracts users most may sometimes be the typical...
Cooperative communications enable single antenna mobiles in a multi-user environment to share their antennas and form a virtual multiple antenna array that allows them to achieve transmit diversity. In order to achieve improved diversity over the classical coded cooperation method in fading channels, we consider a coded cooperation diversity strategy that is suitable for multiple relays channels....
Block diagonalization (BD) algorithm is an efficient precoding technique for multiuser multiple-input multiple-output (MU-MIMO) system. In previous researches, BD precoding was mostly realized based on the singular value decomposition (SVD). However, in the cooperative transmission scenario where the dimension of channel matrix is significantly enlarged compared with the single base station (BS) transmission...
Abstract-Single and Multi-layer adaptive eigen based beamforming (EBB) has been proved to be a promising method to achieve the tradeoff between diversity and spatial multiplexing. But the CQI in multi-layer mode is calculated according to the CQI in single-layer mode. Lack of accurate multi-layer CQI will induce performance loss when implementing layer adaptation at eNodeB. In this paper, aiming to...
In real environments, channel reciprocity cannot be directly exploited between uplink and downlink in time-division duplex (TDD) due to antenna gain mismatch. Previous work about antenna calibration mainly focused on single cell. This work proposes an adaptive scheme for antenna calibration between two cooperative BSs. The proposed scheme aims at achieving an equal ratio between antenna transmitter...
Transmit diversity can be regarded as a technology in wireless communication in order to enhance the system performance. Some relevant methods of transmit diversity have been presented on the basis of link-level research but do not consider multiple access interference (MAI) existing among users in the uplink of multi-user system. In this paper, we proposed one uplink transmit diversity scheme, which...
The virtual MIMO (V-MIMO) and coordinated multipoint transmission (CoMP) are adopted by the LTE system to extend the uplink spectral efficiency. V-MIMO makes use of spatial multiplexing to increase system throughput while CoMP by means of mitigating inter cell interference (ICI) significantly achieve the same effect. In this paper, we present an orthogonality based proportional fair scheduling (OPF)...
Antenna gain mismatch between transmitter and receiver circuits has been regarded as an obstacle for exploiting channel reciprocity between uplink and downlink channels in time-division duplex (TDD) multiple-input multiple-output (MIMO) systems. To the best knowledge of the authors, little work to date has been on about the impact of antenna mismatches on the precoding vector. Motivated by this fact,...
The asymptotic performance of transmit antenna selection (TAS) in a two-hop amplify-and-forward (AF) MIMO relay network over Rayleigh-fading channels is analyzed. Assuming that the source and destination are equipped with NS and ND antennas, respectively, and communicate with each other with the help of an NR-antenna relay, we derive closed-form statistics of received signal-to-noise ratio (SNR) around...
Random Network Coding (RNC) has emerged as an important technology in wireless communication. The present paper proposes a novel cooperative Virtual-MIMO (V-MIMO) structure by applying RNC to the cooperative transmission. Then the diversity gain of the RNC-based cooperative strategy is analyzed and compared with the conventional cooperative strategies. Higher diversity gain or multiplexing gain can...
The performance of transmit antenna selection (TAS) in a two-hop amplify-and-forward (AF) MIMO relaying network over Rayleigh-fading channels is analyzed. Assuming that the source, destination are equipped with NS and ND antennas, respectively, and communicate with each other with the help of an NR-antenna relay, we derive closed-form cumulative distribution function (CDF) of received signal-to-noise...
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...
A novel spatial-multiplexing orthogonal frequency- division multiplexing (OFDM) transmission system with transmit diversity provided by space-frequency block code (SFBC) is proposed in this paper. The proposed scheme combines Alamouti scheme and Bell Labs layered space-time (BLAST) together, thus can achieve transmit diversity and spatial multiplexing gains altogether. Two-step iterative detection...
Coordinated Multi-Point (CoMP) Transmission/Rec-eption technology has shown to improve the system performance. In Time-division duplex system, it can easily obtain channel information by the channel reciprocity. However, a crucial point to realize the channel reciprocity is the antenna calibration problem. This paper aims at analyzing the impact of un-calibrated channel on the precoding matrix under...
For orthogonal frequency-division multiplexing (OFDM) systems, the length of cyclic prefix (CP) is selected on the basis of the maximum delay spread of channel. However, the use of a CP reduces both the spectral efficiency and the power efficiency. In this paper, we proposed an iterative receiver for the space frequency block code (SFBC) OFDM system without CP. After tail cancellation, our proposed...
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