Pub Date : 2001-07-04DOI: 10.1109/EURCON.2001.937798
B. Klepec, A. Kos
IP networks were designed to support non-real time applications, such as file transfer or e-mail. These applications are characterised by their bursty traffic and high bandwidth demands at burst times, but they are not highly sensitive to delay or delay variation (jitter). On the other hand, the VoIP application requires timely packet delivery with low delay, jitter and packet loss values. Integration of voice and data onto a single network is becoming a priority for many network operators. To achieve that goal, IP networks must be enhanced with mechanisms that ensure the quality of service required to carry real-time traffic such as voice. Three parameters emerge as the primary factors affecting voice quality within networks that offer VoIP technologies: clarity, end-to-end delay and echo. To support interactive voice applications on an IP network, we must be able to control four QoS categories: bandwidth, delay (latency), jitter and packet loss. In this paper, we present the behaviour of packet transit times for a VoIP application that produces an 8 kbps data stream. We simulate a simple network with one upstream, one downstream and one backbone link. Two scheduling principles are configured in network nodes (routers): FIFO and priority queuing. We present probability distribution functions for packet delay of VoIP traffic at different network loads. We then compare the performance of VoIP applications on the network with priority queuing (voice having priority over data) and FIFO queuing.
{"title":"Performance of VoIP applications in a simple differentiated services network architecture","authors":"B. Klepec, A. Kos","doi":"10.1109/EURCON.2001.937798","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937798","url":null,"abstract":"IP networks were designed to support non-real time applications, such as file transfer or e-mail. These applications are characterised by their bursty traffic and high bandwidth demands at burst times, but they are not highly sensitive to delay or delay variation (jitter). On the other hand, the VoIP application requires timely packet delivery with low delay, jitter and packet loss values. Integration of voice and data onto a single network is becoming a priority for many network operators. To achieve that goal, IP networks must be enhanced with mechanisms that ensure the quality of service required to carry real-time traffic such as voice. Three parameters emerge as the primary factors affecting voice quality within networks that offer VoIP technologies: clarity, end-to-end delay and echo. To support interactive voice applications on an IP network, we must be able to control four QoS categories: bandwidth, delay (latency), jitter and packet loss. In this paper, we present the behaviour of packet transit times for a VoIP application that produces an 8 kbps data stream. We simulate a simple network with one upstream, one downstream and one backbone link. Two scheduling principles are configured in network nodes (routers): FIFO and priority queuing. We present probability distribution functions for packet delay of VoIP traffic at different network loads. We then compare the performance of VoIP applications on the network with priority queuing (voice having priority over data) and FIFO queuing.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122305334","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 : 2001-07-04DOI: 10.1109/EURCON.2001.937792
N. Suehiro, N. Kuroyanagi, P. Fan, T. Imoto
For future mobile systems, frequency usage efficiency is most important as demand for the wireless frequency band increases. Because both TDMA and FDMA use sine wave, it is very difficult to divide the faded sine wave into original sine wave and the multipath sine waves. On the other hand, because CDMA uses sequences of "chips", where each chip has its "address" in the sequence, their may be some method to divide the original signal and the multipath signals. In fact, when we use a pilot signal, both of whose frequency and time are the same as the signals which bear the data, we can divide the original signal and the multipath signals by using clever codes and modulation. Different signal design methods have been proposed using complete complementary code. In this paper, we propose a new simple method for using the complete complementary code. When we use a complementary code composed of 16 auto-complementary codes, where each auto-complementary code is composed of 16 binary sequences of length 256, we can assign 1 auto-complementary code to pilot signals and 15 auto-complementary codes to information transmission signals. Using the new method on convoluted QPSK signals, 40 Mbit/sec information transmission is realizable on 26 MHz bandwidth.
{"title":"Very efficient wireless frequency usage system using convolutional spread time signals based on multipath estimation in correlation domain","authors":"N. Suehiro, N. Kuroyanagi, P. Fan, T. Imoto","doi":"10.1109/EURCON.2001.937792","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937792","url":null,"abstract":"For future mobile systems, frequency usage efficiency is most important as demand for the wireless frequency band increases. Because both TDMA and FDMA use sine wave, it is very difficult to divide the faded sine wave into original sine wave and the multipath sine waves. On the other hand, because CDMA uses sequences of \"chips\", where each chip has its \"address\" in the sequence, their may be some method to divide the original signal and the multipath signals. In fact, when we use a pilot signal, both of whose frequency and time are the same as the signals which bear the data, we can divide the original signal and the multipath signals by using clever codes and modulation. Different signal design methods have been proposed using complete complementary code. In this paper, we propose a new simple method for using the complete complementary code. When we use a complementary code composed of 16 auto-complementary codes, where each auto-complementary code is composed of 16 binary sequences of length 256, we can assign 1 auto-complementary code to pilot signals and 15 auto-complementary codes to information transmission signals. Using the new method on convoluted QPSK signals, 40 Mbit/sec information transmission is realizable on 26 MHz bandwidth.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116481981","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 : 2001-07-04DOI: 10.1109/EURCON.2001.937777
Xiaomin Ma, Yun Liu, K. Trivedi, Yue Ma, J.J. Han
Soft handoff in the CDMA cellular system is analyzed. To improve performance degradation due to channel resource shortage during soft handoff, we propose a new scheme which converts channels occupied by some pseudo-handoff calls to new handoff calls. Stochastic reward net (SRN) models for our scheme are constructed and solved by SPNP (Stochastic Petri Net Package). The numerical results show that our scheme can decrease both the dropped handoff calls and the blocked new calls.
{"title":"A new handoff scheme for decreasing both dropped calls and blocked calls in CDMA system","authors":"Xiaomin Ma, Yun Liu, K. Trivedi, Yue Ma, J.J. Han","doi":"10.1109/EURCON.2001.937777","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937777","url":null,"abstract":"Soft handoff in the CDMA cellular system is analyzed. To improve performance degradation due to channel resource shortage during soft handoff, we propose a new scheme which converts channels occupied by some pseudo-handoff calls to new handoff calls. Stochastic reward net (SRN) models for our scheme are constructed and solved by SPNP (Stochastic Petri Net Package). The numerical results show that our scheme can decrease both the dropped handoff calls and the blocked new calls.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"2015 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132560509","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 : 2001-07-04DOI: 10.1109/EURCON.2001.937790
I. Dotlic, A. Zejak
A novel method for suppressing antenna array radiation pattern sidelobes while keeping the main lobe width constant has been proposed. The method is based on the IRLS (iterative reweighted least squares) algorithm, which has found wide application in the field of radar pulse compression. The algorithm is not restricted by the array geometry and the mutual element coupling and has no limitations regarding the array excitation coefficients and array radiation pattern. In comparison with the ECF (envelope constrained filter) method, it showed much better results in sidelobe suppression. The algorithm implementation is simple and straightforward.
{"title":"Pattern sidelobe level suppression on antenna array with arbitrary geometry by the IRLS algorithm","authors":"I. Dotlic, A. Zejak","doi":"10.1109/EURCON.2001.937790","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937790","url":null,"abstract":"A novel method for suppressing antenna array radiation pattern sidelobes while keeping the main lobe width constant has been proposed. The method is based on the IRLS (iterative reweighted least squares) algorithm, which has found wide application in the field of radar pulse compression. The algorithm is not restricted by the array geometry and the mutual element coupling and has no limitations regarding the array excitation coefficients and array radiation pattern. In comparison with the ECF (envelope constrained filter) method, it showed much better results in sidelobe suppression. The algorithm implementation is simple and straightforward.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131779742","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 : 2001-07-04DOI: 10.1109/EURCON.2001.937791
K. Williams, A. Curley, M. Tunnicliffe, P. Barrett, P. Scott, J. Ferguson
A microwave band pass filter centred at 10 GHz was designed and fabricated using screen printed, photoimageable thick film technology. The same design was also fabricated using traditional thin film technology as a comparison. Both techniques were successful and showed little differences between them. Photoimageable thick film technology was seen to be a good alternative for low cost, high frequency applications in this instance.
{"title":"Thick film technology for wireless applications","authors":"K. Williams, A. Curley, M. Tunnicliffe, P. Barrett, P. Scott, J. Ferguson","doi":"10.1109/EURCON.2001.937791","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937791","url":null,"abstract":"A microwave band pass filter centred at 10 GHz was designed and fabricated using screen printed, photoimageable thick film technology. The same design was also fabricated using traditional thin film technology as a comparison. Both techniques were successful and showed little differences between them. Photoimageable thick film technology was seen to be a good alternative for low cost, high frequency applications in this instance.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128267550","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 : 2001-07-04DOI: 10.1109/EURCON.2001.937757
Vojin Šenk, P. Radivojac
A new parallel procedure for decoding trellis codes with a large constraint length is simulated and compared to the bidirectional stack algorithm. The systolic organization of processing units arranged in two mutually connected arrays enables the decoding effort to be unaffected by single correctable bursts of errors whose branch length is not greater than some /spl tau/, where /spl tau/ is not greater than the code memory length. During the course of decoding, the algorithm produces a set of tentative decisions of increasing reliability, until it reaches the final decision. Every tentative decision is composed of a portion of a forward and backward path, connected via a tunnel of length /spl tau/. After each new tentative decision is made, a new set of discarding criteria is produced. According to these criteria, a vast number of partially explored paths is discarded from all the stacks, speeding up the decoding procedure. The results show a significant reduction in decoding effort (measured by the number of extended paths in parallel) compared to known sequential procedures.
{"title":"A new bidirectional algorithm for decoding trellis codes","authors":"Vojin Šenk, P. Radivojac","doi":"10.1109/EURCON.2001.937757","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937757","url":null,"abstract":"A new parallel procedure for decoding trellis codes with a large constraint length is simulated and compared to the bidirectional stack algorithm. The systolic organization of processing units arranged in two mutually connected arrays enables the decoding effort to be unaffected by single correctable bursts of errors whose branch length is not greater than some /spl tau/, where /spl tau/ is not greater than the code memory length. During the course of decoding, the algorithm produces a set of tentative decisions of increasing reliability, until it reaches the final decision. Every tentative decision is composed of a portion of a forward and backward path, connected via a tunnel of length /spl tau/. After each new tentative decision is made, a new set of discarding criteria is produced. According to these criteria, a vast number of partially explored paths is discarded from all the stacks, speeding up the decoding procedure. The results show a significant reduction in decoding effort (measured by the number of extended paths in parallel) compared to known sequential procedures.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125078599","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 : 2001-07-04DOI: 10.1109/EURCON.2001.937803
D. Bogojevic
This paper analyses relations between economic development, information communications market and penetration of telecommunication information on European regional, sub-regional and national levels. One model for telecommunication development, potentially adequate for some European countries, is described. According to the results, a general proposal for accelerating penetration through the information communications market is proposed.
{"title":"A telecommunication model for developing European countries","authors":"D. Bogojevic","doi":"10.1109/EURCON.2001.937803","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937803","url":null,"abstract":"This paper analyses relations between economic development, information communications market and penetration of telecommunication information on European regional, sub-regional and national levels. One model for telecommunication development, potentially adequate for some European countries, is described. According to the results, a general proposal for accelerating penetration through the information communications market is proposed.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125111650","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 : 2001-07-04DOI: 10.1109/EURCON.2001.937764
S. Vieira
In this paper, we investigate the issues related to routing connections that request quality of service (QoS) guarantees in the form of end-to-end delay bounds. We assume that the connection scheduling, connection admissibility and state advertisement at every node is based on the rate-controlled static priority (RCSP) algorithm. We provide conditions that efficiently find a path that satisfies the QoS constraints and that also lead to efficient state updates.
{"title":"Quality of service routing with static priority state advertisement","authors":"S. Vieira","doi":"10.1109/EURCON.2001.937764","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937764","url":null,"abstract":"In this paper, we investigate the issues related to routing connections that request quality of service (QoS) guarantees in the form of end-to-end delay bounds. We assume that the connection scheduling, connection admissibility and state advertisement at every node is based on the rate-controlled static priority (RCSP) algorithm. We provide conditions that efficiently find a path that satisfies the QoS constraints and that also lead to efficient state updates.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127807204","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 : 2001-07-04DOI: 10.1109/EURCON.2001.938144
Mo Chun Man, V.K. Wei
Although attacks from a hostile environment to mobile agents have been studied, there is still no formal classification of these attacks. This paper examines possible attacks and presents a taxonomy of attacks on mobile agents in a hostile environment. Our taxonomy is complete in the sense that any possible attack is composed entirely of elements classified by the taxonomy. First, a definition of attack is introduced. Then all possible attacks on mobile agents are classified. This taxonomy is used in the analysis of existing schemes and their appropriateness when applied to certain kind of applications. It is also helpful in directing new protection schemes for mobile agents.
{"title":"A taxonomy for attacks on mobile agent","authors":"Mo Chun Man, V.K. Wei","doi":"10.1109/EURCON.2001.938144","DOIUrl":"https://doi.org/10.1109/EURCON.2001.938144","url":null,"abstract":"Although attacks from a hostile environment to mobile agents have been studied, there is still no formal classification of these attacks. This paper examines possible attacks and presents a taxonomy of attacks on mobile agents in a hostile environment. Our taxonomy is complete in the sense that any possible attack is composed entirely of elements classified by the taxonomy. First, a definition of attack is introduced. Then all possible attacks on mobile agents are classified. This taxonomy is used in the analysis of existing schemes and their appropriateness when applied to certain kind of applications. It is also helpful in directing new protection schemes for mobile agents.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129948617","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 : 2001-07-04DOI: 10.1109/EURCON.2001.938172
S. Vlahoyiannatos, S. Ng, L. Hanzo
Per-survivor processing (PSP)-based blind turbo equalization is combined with various coded modulation schemes, which employ combined modulation and channel coding techniques. The proposed method exploits the enhanced data protection offered by either trellis-coded modulation (TCM), bit-interleaved coded modulation (BICM) or turbo-TCM (TTCM) and exhibits good performance in terms of its output bit error rate (BER). Explicitly, a BER comparable to that of a trained turbo equaliser is attained at the cost of a modest complexity increase.
{"title":"Combined trellis-coded modulation and blind turbo equalisation","authors":"S. Vlahoyiannatos, S. Ng, L. Hanzo","doi":"10.1109/EURCON.2001.938172","DOIUrl":"https://doi.org/10.1109/EURCON.2001.938172","url":null,"abstract":"Per-survivor processing (PSP)-based blind turbo equalization is combined with various coded modulation schemes, which employ combined modulation and channel coding techniques. The proposed method exploits the enhanced data protection offered by either trellis-coded modulation (TCM), bit-interleaved coded modulation (BICM) or turbo-TCM (TTCM) and exhibits good performance in terms of its output bit error rate (BER). Explicitly, a BER comparable to that of a trained turbo equaliser is attained at the cost of a modest complexity increase.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124023591","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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