Time of Arrival Estimation in Probability-Controlled Generalized CDMA Systems
In recent years, more and more wireless communications systems are required to provide also a positioning measurement. In code division multiple access (CDMA) communication systems, the positioning accuracy is significantly degraded by the multiple access interference (MAI) caused by other users in...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2007-11-01
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| Series: | EURASIP Journal on Advances in Signal Processing |
| Online Access: | http://dx.doi.org/10.1155/2008/170804 |
| _version_ | 1811325516780666880 |
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| author | Hagit Messer Efrat Isack Itsik Bergel |
| author_facet | Hagit Messer Efrat Isack Itsik Bergel |
| author_sort | Hagit Messer |
| collection | DOAJ |
| description | In recent years, more and more wireless communications systems are required to provide also a positioning measurement. In code division multiple access (CDMA) communication systems, the positioning accuracy is significantly degraded by the multiple access interference (MAI) caused by other users in the system. This MAI is commonly managed by a power control mechanism, and yet, MAI has a major effect on positioning accuracy. Probability control is a recently introduced interference management mechanism. In this mechanism, a user with excess power chooses not to transmit some of its symbols. The information in the nontransmitted symbols is recovered by an error-correcting code (ECC), while all other users receive a more reliable data during these quiet periods. Previous research had shown that the implementation of a probability control mechanism can significantly reduce the MAI. In this paper, we show that probability control also improves the positioning accuracy. We focus on time-of-arrival (TOA) based positioning systems. We analyze the TOA estimation performance in a generalized CDMA system, in which the probability control mechanism is employed, where the transmitted signal is noncontinuous with a symbol transmission probability smaller than 1. The accuracy of the TOA estimation is determined using appropriate modifications of the Cramer-Rao bound on the delay estimation. Keeping the average transmission power constant, we show that the TOA accuracy of each user does not depend on its transmission probability, while being a nondecreasing function of the transmission probability of any other user. Therefore, a generalized, noncontinuous CDMA system with a probability control mechanism can always achieve better positioning performance, for all users in the network, than a conventional, continuous, CDMA system. |
| first_indexed | 2024-04-13T14:34:36Z |
| format | Article |
| id | doaj.art-1b05a549c3354ee897820f376eea30b0 |
| institution | Directory Open Access Journal |
| issn | 1687-6172 |
| language | English |
| last_indexed | 2024-04-13T14:34:36Z |
| publishDate | 2007-11-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | EURASIP Journal on Advances in Signal Processing |
| spelling | doaj.art-1b05a549c3354ee897820f376eea30b02022-12-22T02:43:04ZengSpringerOpenEURASIP Journal on Advances in Signal Processing1687-61722007-11-01200810.1155/2008/170804Time of Arrival Estimation in Probability-Controlled Generalized CDMA SystemsHagit MesserEfrat IsackItsik BergelIn recent years, more and more wireless communications systems are required to provide also a positioning measurement. In code division multiple access (CDMA) communication systems, the positioning accuracy is significantly degraded by the multiple access interference (MAI) caused by other users in the system. This MAI is commonly managed by a power control mechanism, and yet, MAI has a major effect on positioning accuracy. Probability control is a recently introduced interference management mechanism. In this mechanism, a user with excess power chooses not to transmit some of its symbols. The information in the nontransmitted symbols is recovered by an error-correcting code (ECC), while all other users receive a more reliable data during these quiet periods. Previous research had shown that the implementation of a probability control mechanism can significantly reduce the MAI. In this paper, we show that probability control also improves the positioning accuracy. We focus on time-of-arrival (TOA) based positioning systems. We analyze the TOA estimation performance in a generalized CDMA system, in which the probability control mechanism is employed, where the transmitted signal is noncontinuous with a symbol transmission probability smaller than 1. The accuracy of the TOA estimation is determined using appropriate modifications of the Cramer-Rao bound on the delay estimation. Keeping the average transmission power constant, we show that the TOA accuracy of each user does not depend on its transmission probability, while being a nondecreasing function of the transmission probability of any other user. Therefore, a generalized, noncontinuous CDMA system with a probability control mechanism can always achieve better positioning performance, for all users in the network, than a conventional, continuous, CDMA system.http://dx.doi.org/10.1155/2008/170804 |
| spellingShingle | Hagit Messer Efrat Isack Itsik Bergel Time of Arrival Estimation in Probability-Controlled Generalized CDMA Systems EURASIP Journal on Advances in Signal Processing |
| title | Time of Arrival Estimation in Probability-Controlled Generalized CDMA Systems |
| title_full | Time of Arrival Estimation in Probability-Controlled Generalized CDMA Systems |
| title_fullStr | Time of Arrival Estimation in Probability-Controlled Generalized CDMA Systems |
| title_full_unstemmed | Time of Arrival Estimation in Probability-Controlled Generalized CDMA Systems |
| title_short | Time of Arrival Estimation in Probability-Controlled Generalized CDMA Systems |
| title_sort | time of arrival estimation in probability controlled generalized cdma systems |
| url | http://dx.doi.org/10.1155/2008/170804 |
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