Pub Date : 2003-04-22DOI: 10.1109/VETECS.2003.1207562
Tao Shu, Z. Niu
In this paper, we study the influence of decoding order on the capacity of multimedia DS-CDMA systems with imperfect successive interference cancellation. In contrast to previous studies, cancellation errors are assumed to be different for different users in this work. For any given decoding order, we derive the necessary power allocation that guarantee the QoS of the multimedia traffic. Based on this result, we provide that instead of the descending order of data rate as suggested in some literature, the system capacity is maximized by decoding users according to the ascending order of cancellation errors. We also prove that this capacity-optimal decoding order that makes total residual interference minimum at the same time. Our results are verified by numerical example.
{"title":"Optimal decoding order and power allocation in multimedia CDMA networks with imperfect successive interference cancellation","authors":"Tao Shu, Z. Niu","doi":"10.1109/VETECS.2003.1207562","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207562","url":null,"abstract":"In this paper, we study the influence of decoding order on the capacity of multimedia DS-CDMA systems with imperfect successive interference cancellation. In contrast to previous studies, cancellation errors are assumed to be different for different users in this work. For any given decoding order, we derive the necessary power allocation that guarantee the QoS of the multimedia traffic. Based on this result, we provide that instead of the descending order of data rate as suggested in some literature, the system capacity is maximized by decoding users according to the ascending order of cancellation errors. We also prove that this capacity-optimal decoding order that makes total residual interference minimum at the same time. Our results are verified by numerical example.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124072917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-04-22DOI: 10.1109/VETECS.2003.1208787
N. Ono, T. Kimura, T. Fujii
In mobile IP, registration of mobile node's care-of addresses (location registration) is an important problem because of an increase of location registration traffics. To solve this problem, "dormant mode host alerting ("IP paging")" and "mobile IP location registration area management" methods, which reduce location registration traffics by setting location registration areas, have been proposed. In this paper, we propose and study a new technique, "autonomous neighbor access router discovery", to be necessary to realize these methods. In this technique, mobile node holds the history of the IP addresses which are acquired whenever mobile node moves to another cell, and sends this history to access router according to the needs. Processing these histories, access router discovers the neighbor access routers' IP addresses. Utilizing this technique, each access router can autonomously construct location registration areas. As a result of the evaluation of the proposed technique, if the 1000 histories are collected at each AR, we found that the IP addresses of 1st and 2nd surrounding cells of each AR can be detected in high accuracy.
{"title":"A study on autonomous neighbor access router discovery for mobile IP","authors":"N. Ono, T. Kimura, T. Fujii","doi":"10.1109/VETECS.2003.1208787","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1208787","url":null,"abstract":"In mobile IP, registration of mobile node's care-of addresses (location registration) is an important problem because of an increase of location registration traffics. To solve this problem, \"dormant mode host alerting (\"IP paging\")\" and \"mobile IP location registration area management\" methods, which reduce location registration traffics by setting location registration areas, have been proposed. In this paper, we propose and study a new technique, \"autonomous neighbor access router discovery\", to be necessary to realize these methods. In this technique, mobile node holds the history of the IP addresses which are acquired whenever mobile node moves to another cell, and sends this history to access router according to the needs. Processing these histories, access router discovers the neighbor access routers' IP addresses. Utilizing this technique, each access router can autonomously construct location registration areas. As a result of the evaluation of the proposed technique, if the 1000 histories are collected at each AR, we found that the IP addresses of 1st and 2nd surrounding cells of each AR can be detected in high accuracy.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124612460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-04-22DOI: 10.1109/VETECS.2003.1207825
Young-Bae Ko, Sung-Ju Lee, Kang-Yong Lee
Routing and multicasting in ad hoc networks is a matured research subject. Most of the proposed algorithms assume a physically flat network architecture with mobile hosts having homogeneous capability in terms of network resources and computing power. In practice however, this assumption often may not hold true since there exist various types of mobile hosts with different role, capacity, and mobility pattern. In the military scenario for instance, the leader of the troop usually has more powerful networking equipment than the private soldiers. In this paper, we consider mobile ad hoc networks that have physically hierarchical architecture where different types of mobile hosts form an ad hoc network hierarchy. We present a novel and simple multicasting framework called PHAM (physical hierarchy-driven ad hoc multicast) for ad hoc networks with such an environment. PHAM builds multicast structure at each level of hierarchy for efficient and scalable multicast message delivery.
{"title":"A multicast protocol for physically hierarchical ad hoc networks","authors":"Young-Bae Ko, Sung-Ju Lee, Kang-Yong Lee","doi":"10.1109/VETECS.2003.1207825","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207825","url":null,"abstract":"Routing and multicasting in ad hoc networks is a matured research subject. Most of the proposed algorithms assume a physically flat network architecture with mobile hosts having homogeneous capability in terms of network resources and computing power. In practice however, this assumption often may not hold true since there exist various types of mobile hosts with different role, capacity, and mobility pattern. In the military scenario for instance, the leader of the troop usually has more powerful networking equipment than the private soldiers. In this paper, we consider mobile ad hoc networks that have physically hierarchical architecture where different types of mobile hosts form an ad hoc network hierarchy. We present a novel and simple multicasting framework called PHAM (physical hierarchy-driven ad hoc multicast) for ad hoc networks with such an environment. PHAM builds multicast structure at each level of hierarchy for efficient and scalable multicast message delivery.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124969568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-04-22DOI: 10.1109/VETECS.2003.1208842
H. Ekstrom, A. Schieder
In this paper, we describe and evaluate a novel active queue management scheme that has been designed to optimize the transport of TCP-based traffic over GERAN 3rd generation wireless links. By means of simulations, we found that this scheme outperforms traditional passive and popular RED queuing schemes both in terms of link utilization and in terms of the amount of queuing delay introduced.
{"title":"Buffer management for the interactive bearer in GERAN","authors":"H. Ekstrom, A. Schieder","doi":"10.1109/VETECS.2003.1208842","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1208842","url":null,"abstract":"In this paper, we describe and evaluate a novel active queue management scheme that has been designed to optimize the transport of TCP-based traffic over GERAN 3rd generation wireless links. By means of simulations, we found that this scheme outperforms traditional passive and popular RED queuing schemes both in terms of link utilization and in terms of the amount of queuing delay introduced.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129421685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-04-22DOI: 10.1109/VETECS.2003.1207200
O. Kato, A. Matsumoto, K. Fukawa, H. Suzuki
This paper investigated the PER and throughput performance of known bits insertion scheme for turbo code in 100 Mbps OFCDM(orthogonal frequency and code division multiplexing) in AWGN and multipath Rayleigh fading channels. The method 1 in which the information rate is reduced by replacing information bits by inserted known bits gives 8% throughput increase. The method 2 in which the information rate is fixed irrespectively of the number of inserted known bits by changing the number of punctured bits in order to get the fixed total FEC coding rate also gives PER and BER improvement compared with the conventional turbo code without known bits insertion when the number of inserted known bits are optimized.
{"title":"Packet error rate analysis and its reduction by known bits insertion for turbo code in 10OMbps OFCDM system","authors":"O. Kato, A. Matsumoto, K. Fukawa, H. Suzuki","doi":"10.1109/VETECS.2003.1207200","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207200","url":null,"abstract":"This paper investigated the PER and throughput performance of known bits insertion scheme for turbo code in 100 Mbps OFCDM(orthogonal frequency and code division multiplexing) in AWGN and multipath Rayleigh fading channels. The method 1 in which the information rate is reduced by replacing information bits by inserted known bits gives 8% throughput increase. The method 2 in which the information rate is fixed irrespectively of the number of inserted known bits by changing the number of punctured bits in order to get the fixed total FEC coding rate also gives PER and BER improvement compared with the conventional turbo code without known bits insertion when the number of inserted known bits are optimized.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128303683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-04-22DOI: 10.1109/VETECS.2003.1207567
I. Sato, T. Fujii
In MC-CDMA system, the combining method based on MMSE criterion is well known as one of the methods that reduce multiple access interference. There are two cases of code spreading; in frequency domain and in time domain. In this paper, we analyse the receiving characteristics using MMSE combining in time-domain code spreading. MMSE combining in time domain cannot work effectively in slow fading channels, because time diversity affected by code spreading cannot be obtained. So, we propose a code spreading method to maximally bring out the effect of MMSE; in this method chips of the spreading code are separated spatially in the time domain so as to reduce time correlation of received level fluctuation and obtain time diversity effect as much as possible. We clarified the proposed method dramatically improved receiving characteristics in slow-to-fast fading environments as time interval between chips is wider.
{"title":"A study on MMSE combining for MC-CDMA","authors":"I. Sato, T. Fujii","doi":"10.1109/VETECS.2003.1207567","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207567","url":null,"abstract":"In MC-CDMA system, the combining method based on MMSE criterion is well known as one of the methods that reduce multiple access interference. There are two cases of code spreading; in frequency domain and in time domain. In this paper, we analyse the receiving characteristics using MMSE combining in time-domain code spreading. MMSE combining in time domain cannot work effectively in slow fading channels, because time diversity affected by code spreading cannot be obtained. So, we propose a code spreading method to maximally bring out the effect of MMSE; in this method chips of the spreading code are separated spatially in the time domain so as to reduce time correlation of received level fluctuation and obtain time diversity effect as much as possible. We clarified the proposed method dramatically improved receiving characteristics in slow-to-fast fading environments as time interval between chips is wider.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128636339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-04-22DOI: 10.1109/VETECS.2003.1207167
Yi Wu, Z. Niu, Junli Zheng, T. Saito
This paper suggests a novel delay NAK retransmission scheme for ARQ protocol based on channel state for reliable data transmission in the terrestrial mobile communication systems. The proposed scheme is an improved version of the automatic repeat request defined in the RLP layer of 3GPP2. We analyze the performance of the proposed scheme and some existent retransmission schemes over a two-states Markov channel model with the concept of matrix functions. The performance improvement of the delay NAK retransmission scheme is also verified on computer simulations. It shows that the drastic enhancement of the transmission reliability and reduction of the power consumption at the mobile host can be achieved at the cost of minor increase in complexity.
{"title":"A delay NAK retransmission scheme based on channel state for mobile multimedia communications","authors":"Yi Wu, Z. Niu, Junli Zheng, T. Saito","doi":"10.1109/VETECS.2003.1207167","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207167","url":null,"abstract":"This paper suggests a novel delay NAK retransmission scheme for ARQ protocol based on channel state for reliable data transmission in the terrestrial mobile communication systems. The proposed scheme is an improved version of the automatic repeat request defined in the RLP layer of 3GPP2. We analyze the performance of the proposed scheme and some existent retransmission schemes over a two-states Markov channel model with the concept of matrix functions. The performance improvement of the delay NAK retransmission scheme is also verified on computer simulations. It shows that the drastic enhancement of the transmission reliability and reduction of the power consumption at the mobile host can be achieved at the cost of minor increase in complexity.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129598064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-04-22DOI: 10.1109/VETECS.2003.1208849
Young-Chai Ko, T. Luo, G. Jeong
The performance analysis of dual (two-branch) MRC under imperfect weight is derived. The weight of the perfect MRC is the conjugate of the channel gain normalized to the noise variance of each branch. On the other hand, the imperfect MRC in this paper means the case that the weight is only the conjugate of the channel gain, not being normalized to the noise variance. Considering the system (or channel) conditions that the noise level of each branch is different, we present the accurate performance analysis of imperfect dual MRC in terms of average combined signal-to-noise ratio (SNR), outage probability and average symbol error rate for arbitrary modulations in closed-form and compare them with the performance of the perfect MRC and the selection combining (SC). The interesting statistical results such as probability density function, cumulative distribution function, and moment generating function of the combined output SNR, which follows the ratio distribution of the square of the sum of the exponential random variables (RVs) to the weighted sum of the exponential RVs are derived. From the performance results we provide the criterion in choosing the imperfect MRC, perfect MRC, or SC depending on the degree of the difference of the noise level between branches.
{"title":"Effect of noise variance in the channel estimation on dual-MRC over Rayleigh fading channels","authors":"Young-Chai Ko, T. Luo, G. Jeong","doi":"10.1109/VETECS.2003.1208849","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1208849","url":null,"abstract":"The performance analysis of dual (two-branch) MRC under imperfect weight is derived. The weight of the perfect MRC is the conjugate of the channel gain normalized to the noise variance of each branch. On the other hand, the imperfect MRC in this paper means the case that the weight is only the conjugate of the channel gain, not being normalized to the noise variance. Considering the system (or channel) conditions that the noise level of each branch is different, we present the accurate performance analysis of imperfect dual MRC in terms of average combined signal-to-noise ratio (SNR), outage probability and average symbol error rate for arbitrary modulations in closed-form and compare them with the performance of the perfect MRC and the selection combining (SC). The interesting statistical results such as probability density function, cumulative distribution function, and moment generating function of the combined output SNR, which follows the ratio distribution of the square of the sum of the exponential random variables (RVs) to the weighted sum of the exponential RVs are derived. From the performance results we provide the criterion in choosing the imperfect MRC, perfect MRC, or SC depending on the degree of the difference of the noise level between branches.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129991889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-04-22DOI: 10.1109/VETECS.2003.1208864
N. D. Vo, T. Le-Ngoc
A fast symbol timing recovery (STR) using feedforward maximum-likelihood estimation and interpolation for burst-mode broadband digital demodulator at the lowest sampling rate equivalent to twice the symbol rate. Both analysis and simulation are used to evaluate the performance of the proposed technique in an additive white Gaussian noise (AWGN) environment. The results show that the proposed scheme offers a very accurate and fast-convergence timing estimation suitable for communication systems using short preamble. The proposed scheme also has a simple structure that facilitates the implementation of low-complexity, and high-speed DSP circuitry.
{"title":"Fast symbol timing recovery techniques for burst-mode digital demodulators","authors":"N. D. Vo, T. Le-Ngoc","doi":"10.1109/VETECS.2003.1208864","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1208864","url":null,"abstract":"A fast symbol timing recovery (STR) using feedforward maximum-likelihood estimation and interpolation for burst-mode broadband digital demodulator at the lowest sampling rate equivalent to twice the symbol rate. Both analysis and simulation are used to evaluate the performance of the proposed technique in an additive white Gaussian noise (AWGN) environment. The results show that the proposed scheme offers a very accurate and fast-convergence timing estimation suitable for communication systems using short preamble. The proposed scheme also has a simple structure that facilitates the implementation of low-complexity, and high-speed DSP circuitry.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"137 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129298269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-04-22DOI: 10.1109/VETECS.2003.1207794
Jianxuan Du, Ye Li
In this paper, we propose a channel estimation algorithm for multiple-input and multiple-output orthogonal frequency for division multiplexing (MIMO-OFDM) systems, which has considerably less leakage than DFT-based channel estimators. This algorithm uses the optimum low-rank channel approximation obtained by tracking the frequency autocorrelation matrix of the channel response. The coefficients corresponding to dominant eigenfactors of the autocorrelation matrix are estimated every OFDM block while the eigenfactors are only updated using the training block that is transmitted every M blocks due to the slowly-varying feature of the frequency autocorrelation. Simulation results show that the proposed algorithm can effectively reduce channel estimation error and thus improve system performance.
{"title":"MIMO-OFDM channel estimation based on subspace tracking","authors":"Jianxuan Du, Ye Li","doi":"10.1109/VETECS.2003.1207794","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207794","url":null,"abstract":"In this paper, we propose a channel estimation algorithm for multiple-input and multiple-output orthogonal frequency for division multiplexing (MIMO-OFDM) systems, which has considerably less leakage than DFT-based channel estimators. This algorithm uses the optimum low-rank channel approximation obtained by tracking the frequency autocorrelation matrix of the channel response. The coefficients corresponding to dominant eigenfactors of the autocorrelation matrix are estimated every OFDM block while the eigenfactors are only updated using the training block that is transmitted every M blocks due to the slowly-varying feature of the frequency autocorrelation. Simulation results show that the proposed algorithm can effectively reduce channel estimation error and thus improve system performance.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122357108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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