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| Title: | Iterative equalization using improved block DFE for synchronous CDMA systems | |
| Author (s): | Sang-Yick Leong Kah-Ping Lee Zheng, Y. Rosa | |
| Department/Lab Affiliations: | Electrical and Computer Engineering Wireless Communications Lab | |
| Keywords: | BER bit error rate block codes block decision feedback equalizer channel coding code division multiple access decision feedback equalisers error statistics extrinsic log-likelihood ratio intersymbol interference iterative equalization multipath channels multiple access interference multiuser detector synchronous CDMA systems trellis codes trellis-based channel decoder | |
| Issue Date: | 2005 | |
| Publisher: | Institute of Electrical and Electronics Engineers | |
| Citation: | Sang-Yick Leong; Kah-Ping Lee; Yahong Rosa Zheng, "Iterative equalization using improved block DFE for synchronous CDMA systems" GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. vol.3, pp. 5 pp.-, 28 Nov.-2 Dec. 2005 | |
| Abstract: | Iterative equalization using optimal multiuser detector and trellis-based channel decoder in coded CDMA systems improves the bit error rate (BER) performance dramatically. However, given large number of users employed in the system over multipath channels causing significant multiple-access interference (MAI) and intersymbol interference (ISI), the optimal multiuser detector is thus prohibitively complex. Therefore, the sub-optimal detectors such as low-complexity linear and non-linear equalizers have to be considered. In this paper, a novel low-complexity block decision feedback equalizer (DFE) is proposed for the synchronous CDMA system. Based on the conventional block DFE, the new method is developed by computing the reliable extrinsic log-likelihood ratio (LLR) using two consecutive received samples rather than one received sample in the literature. At each iteration, the estimated symbols by the equalizer is then saved as a priori information for next iteration. Simulation results demonstrate that the proposed low-complexity block DFE algorithm offers very good performance gain over the conventional block DFE. | |
| Type: | Article - Conference proceedings text | |
| Copyright Notice: | This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder. FULL COPYRIGHT INFORMATION: | |
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| title | Iterative equalization using improved block DFE for synchronous CDMA systems | |
| contributor.author | Sang-Yick Leong | |
| contributor.author | Kah-Ping Lee | |
| contributor.author | Zheng, Y. Rosa | |
| contributor.deptlab | Electrical and Computer Engineering | |
| contributor.deptlab | Wireless Communications Lab | |
| subject | BER | |
| subject | bit error rate | |
| subject | block codes | |
| subject | block decision feedback equalizer | |
| subject | channel coding | |
| subject | code division multiple access | |
| subject | decision feedback equalisers | |
| subject | error statistics | |
| subject | extrinsic log-likelihood ratio | |
| subject | intersymbol interference | |
| subject | iterative equalization | |
| subject | multipath channels | |
| subject | multiple access interference | |
| subject | multiuser detector | |
| subject | synchronous CDMA systems | |
| subject | trellis codes | |
| subject | trellis-based channel decoder | |
| date.issued | 2005 | |
| date.submitted | 2007 | |
| publisher | Institute of Electrical and Electronics Engineers | |
| identifier.citation | Sang-Yick Leong; Kah-Ping Lee; Yahong Rosa Zheng, "Iterative equalization using improved block DFE for synchronous CDMA systems" GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. vol.3, pp. 5 pp.-, 28 Nov.-2 Dec. 2005 | |
| identifier.pub.URI | ||
| description.abstract | Iterative equalization using optimal multiuser detector and trellis-based channel decoder in coded CDMA systems improves the bit error rate (BER) performance dramatically. However, given large number of users employed in the system over multipath channels causing significant multiple-access interference (MAI) and intersymbol interference (ISI), the optimal multiuser detector is thus prohibitively complex. Therefore, the sub-optimal detectors such as low-complexity linear and non-linear equalizers have to be considered. In this paper, a novel low-complexity block decision feedback equalizer (DFE) is proposed for the synchronous CDMA system. Based on the conventional block DFE, the new method is developed by computing the reliable extrinsic log-likelihood ratio (LLR) using two consecutive received samples rather than one received sample in the literature. At each iteration, the estimated symbols by the equalizer is then saved as a priori information for next iteration. Simulation results demonstrate that the proposed low-complexity block DFE algorithm offers very good performance gain over the conventional block DFE. | |
| type | Article - Conference proceedings | |
| type.DCMIType | text | |
| type.status | Final version | |
| rights | This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder. | |
| rights.URI | ||
| date.accessioned | 2007-04-05T14:25:58Z | |
| date.available | 2007-04-05T14:25:57Z | |
| identifier.persist.URI | ||
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