Performance of multicode DS-CDMA using frequency domain equalisation in frequency selective fading channel

Adachi, Fumiyuki; Sao, Tomoki; Itagaki, Tomoko

doi:10.1049/el:20030160

Cited by 95 publications

(68 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The minimum mean square error based frequency-domain equalization (MMSE-FDE) can improve the bit error rate (BER) performance of single-carrier (SC) transmission with a low computational complexity [2,3]. However, a big performance gap from the matched filter (MF) bound [4] still exists due to the presence of the residual inter-symbol interference (ISI) after FDE [5].…”

Section: Imentioning

confidence: 99%

See 1 more Smart Citation

2-Step QRM-MLBD Using Detection Ordering for Single-Carrier Transmission

Temma

Yamamoto

Adachi

2012

2012 IEEE 75th Vehicular Technology Conference (VTC Spring)

View full text Add to dashboard Cite

Abstract-2-step maximum likelihood block signal detection employing QR decomposition and M-algorithm (QRM-MLBD) can significantly improve the bit error rate (BER) performance of single-carrier (SC) transmission while reducing the computational complexity compared to maximum likelihood detection (MLD). In 2-step QRM-MLBD, unreliable symbol candidates are removed by performing minimum mean square error based frequency-domain equalization (MMSE-FDE) prior to QRM-MLBD. However, a large number M of surviving paths is still required in the M-algorithm to achieve a BER performance close to the matched filter (MF) bound. In this paper, to remedy this problem, we introduce a detection ordering to 2-step QRM-MLBD. We will show by computer simulation that the use of detection ordering can achieve the same BER performance as 2-step QRM-MLBD while reducing the computational complexity. Keywords-component; Single-carrier, near maximum likelihood detection, MMSE-FDE, QR decomposition, M-algorithm I.INTRODUCTION The broadband wireless channel is composed of many propagation paths with different time delays and therefore, the channel becomes severely frequency-selective [1]. The minimum mean square error based frequency-domain equalization (MMSE-FDE) can improve the bit error rate (BER) performance of single-carrier (SC) transmission with a low computational complexity [2,3]. However, a big performance gap from the matched filter (MF) bound [4] still exists due to the presence of the residual inter-symbol interference (ISI) after FDE [5]. Although the maximum likelihood detection (MLD) [6] is the optimum signal detection, its computational complexity is extremely high.Maximum likelihood block signal detection employing QR decomposition and M-algorithm (QRM-MLBD) [7] was proposed for SC transmission over a frequency-selective fading channel [8,9]. QRM-MLBD can achieve a BER performance close to the MF bound with less complexity than MLD. However, its computational complexity is still high. In order to reduce the computational complexity, we proposed 2-step QRM-MLBD [10,11] which discards unreliable symbol candidates by performing MMSE-FDE prior to QRM-MLBD. However, a large number M of surviving paths is required in the M-algorithm to achieve a BER performance close to the MF bound. In this paper, to remedy this problem, we introduce the detection ordering. The idea of detection ordering was proposed for multiple-input multiple-output (MIMO) system based on the observation that channels have different conditions [12,13]. However, in SC block transmission, the

show abstract

Section: Imentioning

confidence: 99%

“…In the first step of 2-step QRM-MLBD, MMSE-FDE is carried out by multiplying Y by the MMSE weight matrix W as [2,3] …”

Section: -Step Qrm-mlbd With Detection Orderingmentioning

confidence: 99%

2-Step QRM-MLBD Using Detection Ordering for Single-Carrier Transmission

Temma

Yamamoto

Adachi

2012

2012 IEEE 75th Vehicular Technology Conference (VTC Spring)

View full text Add to dashboard Cite

show abstract

“…The conventional minimum mean square error based frequency-domain equalization (MMSE-FDE) improves the SC transmission performance [3,4], but it exhibits still a big performance gap from MF bound [5].…”

Section: Introductionmentioning

confidence: 99%

Overlap QRM-ML Block Signal Detection for Single-Carrier Transmission without CP Insertion

Moroga

Yamamoto

Adachi

2012

2012 IEEE 75th Vehicular Technology Conference (VTC Spring)

View full text Add to dashboard Cite

Abstract-A block signal maximum likelihood detection (MLD) employing QR decomposition and M-algorithm (QRM-MLBD) can significantly improve the bit error rate (BER) performance of the single carrier (SC) transmissions in a frequency-selective fading channel, compared to the conventional frequency-domain equalization (FDE). In QRM-MLBD, the cyclic prefix (CP) is inserted in order to avoid inter-block interference (IBI). However, the CP insertion reduces the transmission efficiency. In this paper, we propose an overlap QRM-MLBD which requires no CP insertion. In overlap QRM-MLBD, IBI can be suppressed by overlapping consecutive observation windows and picking up only the reliable part after the block signal detection. We evaluate the average BER performance and the throughput performance by computer simulation to compare with the conventional QRM-MLBD with CP insertion.

show abstract

“…The gigabit wireless channel is severely frequency-selective and severe inter-symbol interference (ISI) is produced. Frequency-domain signal processing, e.g., frequency-domain equalization (FDE) [2], [3], may play an important role in achieving a good signal transmission performance in such a severe frequency-selective channel. In addition to the above, the path loss and shadowing loss cause a severe received signal power drop since the transmit power is limited.…”

Section: Introductionmentioning

confidence: 99%