Pub Date : 2000-02-15DOI: 10.1109/IZSBC.2000.829267
H. Sari
This paper investigates the application of code-division multiple access (CDMA) to local multipoint distribution services (LMDS) networks. Our analysis shows that while conventional CDMA is superior to time-division multiple access (TDMA) in terms of worst-case interference on the upstream channel, it leads to higher interference on the downstream channel. Next, based on the observation that strong interference occurs only for a small range of user locations, we introduce a multimode CDMA concept which assigns orthogonal spreading sequences whose number and length are a function of the user position with respect to the base station (BS). We show that in terms of worst-case signal-to-interference ratio (SIR), the proposed technique leads to a substantial improvement with respect to conventional CDMA and TDMA.
{"title":"A multimode CDMA scheme with reduced intercell interference for LMDS networks","authors":"H. Sari","doi":"10.1109/IZSBC.2000.829267","DOIUrl":"https://doi.org/10.1109/IZSBC.2000.829267","url":null,"abstract":"This paper investigates the application of code-division multiple access (CDMA) to local multipoint distribution services (LMDS) networks. Our analysis shows that while conventional CDMA is superior to time-division multiple access (TDMA) in terms of worst-case interference on the upstream channel, it leads to higher interference on the downstream channel. Next, based on the observation that strong interference occurs only for a small range of user locations, we introduce a multimode CDMA concept which assigns orthogonal spreading sequences whose number and length are a function of the user position with respect to the base station (BS). We show that in terms of worst-case signal-to-interference ratio (SIR), the proposed technique leads to a substantial improvement with respect to conventional CDMA and TDMA.","PeriodicalId":409898,"journal":{"name":"2000 International Zurich Seminar on Broadband Communications. Accessing, Transmission, Networking. Proceedings (Cat. No.00TH8475)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130793926","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 : 2000-02-15DOI: 10.1109/IZSBC.2000.829242
M. Flament, M. Unbehaun
Due to the growing interest in mobile data applications, the Global System for Mobile communications (GSM) has been extended by the General Packet Radio Service (GPRS). It allows the transmission of packet data at moderate bit rates using random access channels within the existing GSM infrastructure. This paper analyses the impact of using multiple channels in a GSM system for GPRS packet transmission. Different combinations of frequency reuse and channel coding are evaluated for 1, 4 and 8 packet data channels (PDCH) per cell. A tight frequency reuse of 1, together with a strong error coding scheme was found to provide the highest capacity. The increased trunking efficiency for a system with 8 PDCH yields a capacity gain of about 64% over a system with only 1 channel. The results indicate that mixing circuit and packet switched traffic causes inefficient use of system resources. Since GSM voice services usually require a frequency reuse of 3 or 7, a separate overlaying network for GPRS provides better resource utilization and maximizes the number of users fulfilling the specified quality of service (QoS) requirements.
{"title":"Frequency reuse and coding for GPRS multi-slot operation","authors":"M. Flament, M. Unbehaun","doi":"10.1109/IZSBC.2000.829242","DOIUrl":"https://doi.org/10.1109/IZSBC.2000.829242","url":null,"abstract":"Due to the growing interest in mobile data applications, the Global System for Mobile communications (GSM) has been extended by the General Packet Radio Service (GPRS). It allows the transmission of packet data at moderate bit rates using random access channels within the existing GSM infrastructure. This paper analyses the impact of using multiple channels in a GSM system for GPRS packet transmission. Different combinations of frequency reuse and channel coding are evaluated for 1, 4 and 8 packet data channels (PDCH) per cell. A tight frequency reuse of 1, together with a strong error coding scheme was found to provide the highest capacity. The increased trunking efficiency for a system with 8 PDCH yields a capacity gain of about 64% over a system with only 1 channel. The results indicate that mixing circuit and packet switched traffic causes inefficient use of system resources. Since GSM voice services usually require a frequency reuse of 3 or 7, a separate overlaying network for GPRS provides better resource utilization and maximizes the number of users fulfilling the specified quality of service (QoS) requirements.","PeriodicalId":409898,"journal":{"name":"2000 International Zurich Seminar on Broadband Communications. Accessing, Transmission, Networking. Proceedings (Cat. No.00TH8475)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133907747","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 : 2000-02-15DOI: 10.1109/IZSBC.2000.829260
Haiying Wang, J. Belzile, C. Despins
In this paper, the simulation results of a 64-QAM OFDM system in a time-selective Rician fading channel are presented. First, results dealing with the improvement of OFDM system performance by waveform shaping and TCM coding in an AWGN channel are reported. Second, coded OFDM system performance in a time-selective Rician fading channel is investigated.
{"title":"64-QAM OFDM with TCM coding and waveform shaping in a time-selective Rician fading channel","authors":"Haiying Wang, J. Belzile, C. Despins","doi":"10.1109/IZSBC.2000.829260","DOIUrl":"https://doi.org/10.1109/IZSBC.2000.829260","url":null,"abstract":"In this paper, the simulation results of a 64-QAM OFDM system in a time-selective Rician fading channel are presented. First, results dealing with the improvement of OFDM system performance by waveform shaping and TCM coding in an AWGN channel are reported. Second, coded OFDM system performance in a time-selective Rician fading channel is investigated.","PeriodicalId":409898,"journal":{"name":"2000 International Zurich Seminar on Broadband Communications. Accessing, Transmission, Networking. Proceedings (Cat. No.00TH8475)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123884265","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 : 2000-02-15DOI: 10.1109/IZSBC.2000.829253
C. Minkenberg, T. Engbersen, Michel Colmant
A novel way of building switch system architectures, based on the combination of an output-buffered switch with input queues that sort arriving packets on a per-output-port basis, is proposed that has a scheduling complexity of O(N). Simulation results to demonstrate the high and robust performance achieved with the proposed system architecture are presented, and a practical implementation is outlined.
{"title":"A robust switch architecture for bursty traffic","authors":"C. Minkenberg, T. Engbersen, Michel Colmant","doi":"10.1109/IZSBC.2000.829253","DOIUrl":"https://doi.org/10.1109/IZSBC.2000.829253","url":null,"abstract":"A novel way of building switch system architectures, based on the combination of an output-buffered switch with input queues that sort arriving packets on a per-output-port basis, is proposed that has a scheduling complexity of O(N). Simulation results to demonstrate the high and robust performance achieved with the proposed system architecture are presented, and a practical implementation is outlined.","PeriodicalId":409898,"journal":{"name":"2000 International Zurich Seminar on Broadband Communications. Accessing, Transmission, Networking. Proceedings (Cat. No.00TH8475)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123576641","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 : 2000-02-15DOI: 10.1109/IZSBC.2000.829258
H. Yoshino, A. Czylwik
This paper proposes a new adaptive co-channel interference (CCI) canceller for an orthogonal frequency division multiplexing (OFDM) scheme. It employs a parametric CCI cancellation scheme, least-mean-squares (LMS) maximum-likelihood estimation (MLE), which simultaneously estimates time-varying channels and transmitted symbols both for desired and CCI signals. Computer simulations were performed on interference canceling characteristics of the proposed CCI canceller both under static and Rayleigh fading conditions, wherein a single CCI is considered. Computer simulations confirm that the proposed canceller attains a BER of 1.5/spl times/10/sup -2/ at a signal-to-interference ratio of -10 dB in Rayleigh fading condition with the maximum Doppler frequency of 52 Hz and average E/sub b//N/sub 0/ of 30 dB.
{"title":"Adaptive co-channel interference (CCI) cancellation for OFDM communication systems","authors":"H. Yoshino, A. Czylwik","doi":"10.1109/IZSBC.2000.829258","DOIUrl":"https://doi.org/10.1109/IZSBC.2000.829258","url":null,"abstract":"This paper proposes a new adaptive co-channel interference (CCI) canceller for an orthogonal frequency division multiplexing (OFDM) scheme. It employs a parametric CCI cancellation scheme, least-mean-squares (LMS) maximum-likelihood estimation (MLE), which simultaneously estimates time-varying channels and transmitted symbols both for desired and CCI signals. Computer simulations were performed on interference canceling characteristics of the proposed CCI canceller both under static and Rayleigh fading conditions, wherein a single CCI is considered. Computer simulations confirm that the proposed canceller attains a BER of 1.5/spl times/10/sup -2/ at a signal-to-interference ratio of -10 dB in Rayleigh fading condition with the maximum Doppler frequency of 52 Hz and average E/sub b//N/sub 0/ of 30 dB.","PeriodicalId":409898,"journal":{"name":"2000 International Zurich Seminar on Broadband Communications. Accessing, Transmission, Networking. Proceedings (Cat. No.00TH8475)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132136909","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 : 1900-01-01DOI: 10.1109/IZSBC.2000.829235
M. Ghavami, R. Kohno
High rate and highly reliable mobile communication systems require methods for acting against fading. One of the measures to cope with fading is spatial division multiple access (SDMA) which distinguishes radio signals in a space or angular domain by using antenna directivity or beamforming according to the direction of arrival (DOA) of signals. Conventional bearing angle estimators suffer from the different precision associated with different angles. The method presented in this paper employs a set of digital two-dimensional filters associated with different angles of arrival. Each filter is a fan filter and performs a broadband characteristic. It is shown that the precision of the bearing estimation is highly dependent upon the angle itself and is maximum in the broadside and minimum in the endfire. The set of filters is then designed according to the criteria obtained by theory, so that the precision at different angles is kept uniform. It is demonstrated by computer simulations that in the presence of noisy broadband incoming signals, the estimation of the arriving angle for different angles is accomplished with the same resolution and hence with this method complex and separately sectored antennas are not required.
{"title":"Bearing estimation with uniform resolution in broadband environments","authors":"M. Ghavami, R. Kohno","doi":"10.1109/IZSBC.2000.829235","DOIUrl":"https://doi.org/10.1109/IZSBC.2000.829235","url":null,"abstract":"High rate and highly reliable mobile communication systems require methods for acting against fading. One of the measures to cope with fading is spatial division multiple access (SDMA) which distinguishes radio signals in a space or angular domain by using antenna directivity or beamforming according to the direction of arrival (DOA) of signals. Conventional bearing angle estimators suffer from the different precision associated with different angles. The method presented in this paper employs a set of digital two-dimensional filters associated with different angles of arrival. Each filter is a fan filter and performs a broadband characteristic. It is shown that the precision of the bearing estimation is highly dependent upon the angle itself and is maximum in the broadside and minimum in the endfire. The set of filters is then designed according to the criteria obtained by theory, so that the precision at different angles is kept uniform. It is demonstrated by computer simulations that in the presence of noisy broadband incoming signals, the estimation of the arriving angle for different angles is accomplished with the same resolution and hence with this method complex and separately sectored antennas are not required.","PeriodicalId":409898,"journal":{"name":"2000 International Zurich Seminar on Broadband Communications. Accessing, Transmission, Networking. Proceedings (Cat. No.00TH8475)","volume":"389 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126969965","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 : 1900-01-01DOI: 10.1109/IZSBC.2000.829221
R. Steele
The evolution of communications and how this is affected by social factors is addressed in an attempt to gaze beyond third generation (3G) systems. We commence by observing the origins of communications and the route we travelled to arrive at the proposed 3G systems. After speculating on what 3G networks are likely to offer and their social impact, we examine future scenarios such as soft telecommunications, high capacity networks, body wireless local area networks (B-WLAN), a myriad of interconnecting WLAN, aerial networks, maritime networks, and ad hoc networks. The discourse culminates with speculation regarding the speeding up of evolution of man to cope with the growing intelligence of our electronics and communications systems.
{"title":"Beyond 3G","authors":"R. Steele","doi":"10.1109/IZSBC.2000.829221","DOIUrl":"https://doi.org/10.1109/IZSBC.2000.829221","url":null,"abstract":"The evolution of communications and how this is affected by social factors is addressed in an attempt to gaze beyond third generation (3G) systems. We commence by observing the origins of communications and the route we travelled to arrive at the proposed 3G systems. After speculating on what 3G networks are likely to offer and their social impact, we examine future scenarios such as soft telecommunications, high capacity networks, body wireless local area networks (B-WLAN), a myriad of interconnecting WLAN, aerial networks, maritime networks, and ad hoc networks. The discourse culminates with speculation regarding the speeding up of evolution of man to cope with the growing intelligence of our electronics and communications systems.","PeriodicalId":409898,"journal":{"name":"2000 International Zurich Seminar on Broadband Communications. Accessing, Transmission, Networking. Proceedings (Cat. No.00TH8475)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134321170","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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