## Iterative (turbo) soft interference cancellation and decoding for coded CDMA (1999)

Venue: | IEEE Trans. Commun |

Citations: | 284 - 13 self |

### BibTeX

@ARTICLE{Wang99iterative(turbo),

author = {Xiaodong Wang and H. Vincent Poor},

title = {Iterative (turbo) soft interference cancellation and decoding for coded CDMA},

journal = {IEEE Trans. Commun},

year = {1999},

volume = {47},

pages = {1046--1061}

}

### Years of Citing Articles

### OpenURL

### Abstract

Abstract — The presence of both multiple-access interference (MAI) and intersymbol interference (ISI) constitutes a major impediment to reliable communications in multipath code-division multiple-access (CDMA) channels. In this paper, an iterative receiver structure is proposed for decoding multiuser information data in a convolutionally coded asynchronous multipath DS-CDMA system. The receiver performs two successive softoutput decisions, achieved by a soft-input soft-output (SISO) multiuser detector and a bank of single-user SISO channel decoders, through an iterative process. At each iteration, extrinsic information is extracted from detection and decoding stages and is then used as a priori information in the next iteration, just as in Turbo decoding. Given the multipath CDMA channel model, a direct implementation of a sliding-window SISO multiuser detector has a prohibitive computational complexity. A low-complexity SISO multiuser detector is developed based on a novel nonlinear interference suppression technique, which makes use of both soft interference cancellation and instantaneous linear minimum mean-square error filtering. The properties of such a nonlinear interference suppressor are examined, and an efficient recursive implementation is derived. Simulation results demonstrate that the proposed low-complexity iterative receiver structure for interference suppression and decoding offers significant performance gain over the traditional noniterative receiver structure. Moreover, at high signal-to-noise ratio, the detrimental effects of MAI and ISI in the channel can almost be completely overcome by iterative processing, and single-user performance can be approached. Index Terms — Coded CDMA, instantaneous MMSE filtering, multiuser detection, soft interference cancellation, Turbo processing.

### Citations

4675 |
Topics in Matrix Analysis
- Horn, Johnson
- 1991
(Show Context)
Citation Context ...with respect to the th column and th row to get , and . By (82), (86) is then equivalent to (87) Since , we have . Therefore in order to show (87) it suffices to show , which is in turn equivalent to =-=[10]-=-, where means that the matrix is positive definite. Since by assumption, , therefore . It is easy to check that APPENDIX B PROOF OF (81) By (75) and (78), in order to show (81), it suffices to show th... |

1304 | Near Shannon limit error-correcting coding and decoding: turbo code - Berrou, Glavieux, et al. |

1202 |
Optimal decoding of linear codes for minimizing symbol error © 2010
- Bahl, Cocke, et al.
- 2010
(Show Context)
Citation Context ...n bits, based on the code constraints. In this section, we outline a procedure for computing the LLR’s of the information and code bits, which is essentially a slight modification of the algorithm in =-=[1]-=-. Consider a binary rate convolutional encoder of overall constraint length . The input to the encoder at time is the block and the corresponding output is . The state of the trellis at time can be re... |

1020 | Multiuser Detection
- Verdu
- 1998
(Show Context)
Citation Context ...t to reliable CDMA communications in multipath channels. Linear techniques for joint multiuser detection and equalization have been proposed as effective ways for combating both types of interference =-=[20]-=-. The purpose of this paper is to develop low-complexity iterative multiuser receivers for coded CDMA systems over multipath channels. The rest of the paper is organized as follows. In Section II, the... |

478 | Near optimum error correcting coding and decoding : Turbo-codes - Berrou, Glavieux - 1996 |

383 |
Minimum probability of error for asynchronous Gaussian multiple access channels
- Verdu
(Show Context)
Citation Context ...TION OVER THE PAST decade, a significant amount of research has addressed various multiuser detection methods for interference suppression in code-division multipleaccess (CDMA) communication systems =-=[19]-=-. The high computational complexity of the optimal multiuser detectors (which is exponential in terms of the number of users in the channel) has motivated the study of a number of low-complexity subop... |

144 | Probability of error in mmse multiuser detection
- Poor, Verdú
- 1997
(Show Context)
Citation Context ...icient and accurate way of computing the extrinsic information (as discussed next), which is vital to the Turbo multiuser receiver. 2) Gaussian Approximation of Soft MMSE Filter Output It is shown in =-=[15]-=- that the distribution of the residual interference-plus-noise at the output of a linear MMSE multiuser detector is well approximated by a Gaussian distribution. In what follows, we assume that the ou... |

115 |
Turbo principle: tutorial introduction and state of the art
- Hagenauer
- 1997
(Show Context)
Citation Context ...inciple can be successfully applied to many detection/decoding problems such as serial concatenated decoding, equalization, coded modulation, multiuser detection and joint source and channel decoding =-=[9]-=-. In particular, a Turbo equalization scheme is proposed in [4] for convolutionally coded digital transmission over intersymbol interference channel. More recently, in [11] an optimal iterative multiu... |

80 |
An iterative multiuser decoder for near-capacity communications
- Moher
- 1998
(Show Context)
Citation Context ... source and channel decoding [9]. In particular, a Turbo equalization scheme is proposed in [4] for convolutionally coded digital transmission over intersymbol interference channel. More recently, in =-=[11]-=- an optimal iterative multiuser detector for synchronous coded CDMA system is derived, based on iterative techniques for cross-entropy minimization. A practical suboptimal implementation is also prese... |

79 |
Near-optimum detection in synchronous code-division multiple-access systems
- Varanasi, Aazhang
- 1991
(Show Context)
Citation Context ...sers actually benefit from the strong interference whereas the strong users suffer performance loss from the weak interference, a phenomenon previously also observed in the optimal multiuser detector =-=[18]-=- and the multistage multiuser detector [17]. Note that with a computational complexity , the exact SISO multiuser detector (28) is not feasible for practical implementation in channels with medium to ... |

43 |
Suboptimum multiuser receivers for convolutionally coded asynchronous DS-CDh4A systems
- Giallorenzi, Wilson
- 1996
(Show Context)
Citation Context ...he asynchronous multiuser detector and the convolutional code, resulting in a prohibitive computational complexity , where is the number of users in the channel, and is the code constraint length. In =-=[7]-=-, some low-complexity receivers which perform multiuser symbol detection and decoding either separately or jointly are studied. Recently iterative (“Turbo”) processing techniques have received conside... |

43 |
Forward Error Correcting for CDMA Systems
- Hagenauer
- 1996
(Show Context)
Citation Context ... element to zero. For each user , a soft interference cancellation is performed on the matched-filter output in (21), to obtain (32) Such a soft interference cancellation scheme was first proposed in =-=[8]-=-. Next, in order to further suppress the residual interference in , an instantaneous linear MMSE filter is applied to , to obtain (33) where the filter is chosen to minimize the meansquare error betwe... |

36 |
et al., ”Iterative correction of intersymbol interference: Turbo equalization
- Douillard
- 1995
(Show Context)
Citation Context ...problems such as serial concatenated decoding, equalization, coded modulation, multiuser detection and joint source and channel decoding [9]. In particular, a Turbo equalization scheme is proposed in =-=[4]-=- for convolutionally coded digital transmission over intersymbol interference channel. More recently, in [11] an optimal iterative multiuser detector for synchronous coded CDMA system is derived, base... |

30 |
New concepts and technologies for achieving highly reliable and high-capacity multimedia wireless communications systems
- Morinaga, Nakagawa, et al.
- 1997
(Show Context)
Citation Context ...networks which would give users access to data rates on the order of 1 to 10’s of Mb/s [5], [14], or even higher ATM (asynchronous transfer mode)-compatible rates for wireless multimedia applications =-=[12]-=-. In a highrate CDMA system, the MAI and the ISI constitute the major impediment to the overall system performance. In this paper, we have developed a low-complexity iterative receiver structure for d... |

16 | Iterated soft decision interference cancellation for CDMA
- Müller, Huber
- 1997
(Show Context)
Citation Context ... (SNR) for the th user, then it is shown in Appendix A that, if , for , then we have (46) Note that iterative soft interference cancellation schemes for uncoded and coded CDMA systems are proposed in =-=[13]-=- and [16], respectively, where no MMSE filtering across the users is performed after the cancellation stage. The instantaneous MMSE filtering proposed here provides an efficient and accurate way of co... |

16 |
Trends in local wireless networks
- Pahlavan, Probert, et al.
- 1995
(Show Context)
Citation Context ...equal power. x aU. VI. CONCLUSION There is currently a significant interest in the design of wide-band CDMA networks which would give users access to data rates on the order of 1 to 10’s of Mb/s [5], =-=[14]-=-, or even higher ATM (asynchronous transfer mode)-compatible rates for wireless multimedia applications [12]. In a highrate CDMA system, the MAI and the ISI constitute the major impediment to the over... |

11 |
Multiuser ML sequence estimator for convolutional coded asynchronous DS-CDMA systems
- Giallorenzi, Wilson
- 1996
(Show Context)
Citation Context ...dulation of multiuser signals. Since in practice, most CDMA systems employ error control coding and interleaving, recent work in this area has addressed multiuser detection for coded CDMA systems. In =-=[6]-=-, it is shown that the optimal decoding scheme for an asynchronous convolutionally coded CDMA system combines the trellises of both the asynchronous multiuser detector and the convolutional code, resu... |

8 |
Iterative multiuser decoding for asynchronous users
- Tarköy
- 1997
(Show Context)
Citation Context ...ference whereas the strong users suffer performance loss from the weak interference, a phenomenon previously also observed in the optimal multiuser detector [18] and the multistage multiuser detector =-=[17]-=-. Note that with a computational complexity , the exact SISO multiuser detector (28) is not feasible for practical implementation in channels with medium to large number of users ; whereas the approxi... |

7 | equalization and multiuser detection for CDMA communications in dispersive channels - Wang, Poor, et al. - 1998 |

5 |
et al., “Iterative Multiuser Detection for CDMA with FEC: Near Single User Performance
- Reed
- 1998
(Show Context)
Citation Context ...ntation is also presented. The computational complexity of this method, however, is , which is still prohibitive for channels with medium to large number of users. A similar work has also appeared in =-=[16]-=-. The presence of both multiple-access interference (MAI) and intersymbol interference (ISI) constitutes a major impediment to reliable CDMA communications in multipath channels. Linear techniques for... |

3 |
LaMaire et al., “Wireless LAN’s and mobile networking: Standard and future directions
- O
- 1996
(Show Context)
Citation Context ...have equal power. x aU. VI. CONCLUSION There is currently a significant interest in the design of wide-band CDMA networks which would give users access to data rates on the order of 1 to 10’s of Mb/s =-=[5]-=-, [14], or even higher ATM (asynchronous transfer mode)-compatible rates for wireless multimedia applications [12]. In a highrate CDMA system, the MAI and the ISI constitute the major impediment to th... |