The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper proposed an efficient iterative frequency domain equalization (FDE) for cooperative multi-relay-assisted automatic repeat request (ARQ) single carrier systems operating over multiple-input-multiple-output (MIMO) channel. The receiver employs each retransmission as an additional set of virtual receive antennas to exploit the space diversity. At each iteration, soft inter-symbol interference...
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...
The codebook based precoding is an effective form of limited feedback closed-loop multiple input multiple output (MIMO) scheme. An efficient methodology to build low complexity and high performance codebook is crucial for the closed-loop MIMO precoding algorithm. In this paper, we present a simplified codebook design scheme for 8-Tx MIMO based on the 4-Tx codebook in LTE Rel-8 and Kronecker product...
In this paper, we consider practical multiuser multiple-input multiple-output (MU-MIMO) systems where each user has multiple receive antennas and limited channel feedback is available at the base station (BS). The joint combiner and precoding scheme for downlink transmission is proposed, in which we consider the joint use of the receive antenna combiner at each user and precoding at the BS. In the...
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,...
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...
Cooperative Communication enables wireless devices with relatively less antennas to share their antennas and create virtual multiple-antenna transmitter, thereby achieving transmit diversity to combat fading caused by multi-path propagation in wireless environment. At the receiver in a multi- input multi-output (MIMO) relay system, we can still utilize the traditional detection algorithm, such as...
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...
It is well-known that, the cyclic prefix (CP) protects orthogonal frequency-division multiplexing (OFDM) system from inter-block interference (IBI), but it also reduces the spectral efficiency. In this paper, a low-complexity turbo equalization algorithm is proposed for multiple input multiple output (MIMO) OFDM system without CP. In our algorithm, tail cancellation is performed firstly by using the...
The maximum likelihood detection with QR decomposition and M-algorithm (QRM-MLD) has been proposed as a near-optimal multiple-input multiple-output (MIMO) detection scheme which can achieve near maximum likelihood (ML) performance with complexity greatly reduced. However, the performance of the QRM-MLD algorithm will deteriorate with the increasing of the number of transmit antennas, as well as the...
A simplified fixed-complexity sphere decoder (SFSD) with much lower computational cost than that of the original fixed-complexity sphere decoder (FSD) has been developed for signal detection in Vertical Bell Laboratories layered space-time (V-BLAST) systems. Simulation results on a 16-QAM system with 8 transmit and 8 receive antennas show that the SFSD can attain the near-optimal performance with...
This paper analyzes the ergodic capacity in Rayeigh fading case and derives the signal-to-noise ratio (SNR) conditions for achieving the lower bound on ergodic capacity when nodes have different number of antennas, especially when the number of source antennas is larger than that of the destination's and the relay transmitter and receiver's. Then we verify it through simulations. Besides, simulation...
This paper proposes an efficient turbo equalization for multiple-input multiple-output (MIMO) single carrier systems with cyclic-prefix (CP). The receiver can effectively conduct inter-symbol interference cancellation (ISIC) and inter-antenna interference cancellation (IAIC) followed by frequency domain equalization (FDE), and the elements of the estimated symbol sequence are demapped onto the bit...
This paper proposes a new approach to apply singular value decomposition (SVD) in fractionally spaced frequency domain equalizer (FSFDE) for the single carrier MIMO-CDMA systems. Multiple data streams can be reliably transmitted through the parallel subchannels by using SVD, which can improve the capacity effectively without increasing frequency bandwidth or the average transmit power. Fractional...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.