Likelihood Function for QRM-MLD Suitable for Soft-Decision Turbo Decoding and Its Performance for OFCDM MIMO Multiplexing in Multipath Fading Channel

VTC-2005-Fall. 2005 IEEE 62nd Vehicular Technology Conference, 2005.

Deepshikha²,

Adachi³

Abstract-In a multicode DS-CDMA transmission, high-speed data rate can be achieved by using orthogonal code multiplexing while retaining the multi access capability. For further increase of the transmission data rate, the use of multi-input multi-output (MIMO) multiplexing is very effective. However, channels become severely frequency-selective, as a result, the performance is severely degraded in a frequency-selective fading channel due to orthogonality distortion among spreading codes. Recently, we proposed an iterative parallel interference cancellation (PIC) for SC-MIMO multiplexing in a frequency-selective fading channel. In this paper, we apply the frequency-domain iterative PIC to multicode DS-CDMA MIMO multiplexing in a frequencyselective fading channel and investigate, by the computer simulation, the impact of spreading factor and channel frequency-selectivity on the achievable bit error rate (BER) performance. Packet access will be the core technology of the next generation mobile communications systems. As an efficient error control technique, rate compatible punctured turbo coded hybrid automatic repeat request (RCPT-HARQ) is well known. We also evaluate, by computer simulation, the throughput performance of RCPT-HARQ in a frequency-selective Rayleigh fading channel.

Section: Computer Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Frequency-domain iterative parallel interference cancellation for multicode DS-CDMA-MIMO multiplexing

VTC-2005-Fall. 2005 IEEE 62nd Vehicular Technology Conference, 2005.

Deepshikha²,

Adachi³

“…One of the promising techniques is the multiple-input multiple-output (MIMO) multiplexing [5][6][7][8][9] that uses multiple transmit and receive antennas. In MIMO multiplexing, transmit data sequence is transformed into parallel sequences and each sequence is transmitted from a different transmit antenna at the same time with the same carrier frequency.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the total transmission rate increases in proportion to the number of transmit antennas without requiring additional bandwidth.. At the receiver, it is necessary to separate the transmit signals. A lot of research attention is given to find the separation methods which provide a performance close to that of maximum likelihood detection (MLD) but with reduced complexity, like Vertical-bell laboratories layered space-time architecture (V-BLAST) [7], MLD using QR decomposition [8] and so on. Recently, we proposed an iterative parallel interference cancellation (PIC) for MIMO multiplexing in a frequency nonselective fading channel [9].…”

Section: Introductionmentioning

confidence: 99%

Throughput of Turbo Coded Hybrid ARQ Using Single-carrier MIMO Multiplexing

2005 IEEE 61st Vehicular Technology Conference

Garg

Adachi

Abstract-Broadband wireless packet access will be the core technology of the next generation mobile communications systems. Very high speed and high quality packet transmissions can be achieved by the joint use of multiple-input multiple-output (MIMO) multiplexing and hybrid ARQ (HARQ). However, if single-carrier (SC) transmission is used, the throughput performance significantly degrades due to large inter-symbol interference (ISI) resulting from severe frequency-selective channel. Recently, we proposed an iterative parallel interference cancellation (PIC) for MIMO multiplexing in a frequency nonselective fading channel. In this paper, we propose a frequencydomain iterative PIC for SC-MIMO multiplexing to separate signals transmitted from different antennas while achieving frequency and antenna diversity gain and evaluate, by computer simulation, the throughput performance of turbo coded HARQ using SC-MIMO multiplexing in a frequency-selective Rayleigh fading channel.

“…At a receiver, it is necessary to separate the signals transmitted from different antennas. A lot of research attention has been paid to find the signal separation methods, which provide a performance close to that of maximum likelihood detection (MLD) but with reduced complexity, like vertical-Bell laboratories layered space-time architecture (V-BLAST) [6], MLD using QR decomposition [7] and so on.…”

Section: Introductionmentioning

confidence: 99%

Iterative Joint PIC and 2D MMSE-FDE for Turbo-coded HARQ with SC-MIMO Multiplexing

2006 IEEE 63rd Vehicular Technology Conference

Adachi

Abstract-Broadband wireless packet access will be the core technology of the next generation mobile communication systems. For very high-speed and high-quality packet transmissions, the joint use of multiple-input multiple-output (MIMO) multiplexing and hybrid ARQ (HARQ) is very effective. However, if single-carrier (SC) transmission is used, the transmission performance significantly degrades due to a large inter-symbol interference (ISI) resulting from a severe frequency-selective fading. Recently, we proposed a frequencydomain iterative parallel interference cancellation (PIC) for SC-MIMO multiplexing. For signal separation, 2 dimensional minimum mean square error (2D MMSE)-FDE is performed at first. Then, the joint PIC and 1D MMSE-FDE is repeated a sufficient number of times. However, the interference from other transmit antennas still remains at the outputs of PIC. Therefore, in this paper, we propose to use 2D MMSE-FDE instead of 1D MMSE-FDE in each iteration and investigate, by computer simulation, the achievable bit error rate (BER) and throughput performance of HARQ in a frequency-selective Rayleigh fading channel.