Pub Date : 2001-11-25DOI: 10.1109/GLOCOM.2001.965833
Yang Chen, M. Hamdi, D. Tsang
Optical burst switching (OBS) is considered as an efficient switching technique for building the next generation optical Internet. An offset-time based scheme has recently been proposed in order to provide quality-of-service (QoS) in OBS networks. Unfortunately, the proposed service differentiation has several problems. The aim of this paper is to address these problems and introduce the concept of proportional QoS into this OBS paradigm. An intentional dropping scheme is proposed so as to give a controllable burst loss probability for different service classes. In order to achieve flexible packet delay differentiation, we extend the well-known waited-time-priority (WTP) scheduler to form a burst assembling scheme. Simulations are conducted to evaluate the performance of our proportional QoS provisioning within OBS networks in terms of burst loss probability and packet delay.
{"title":"Proportional QoS over OBS networks","authors":"Yang Chen, M. Hamdi, D. Tsang","doi":"10.1109/GLOCOM.2001.965833","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965833","url":null,"abstract":"Optical burst switching (OBS) is considered as an efficient switching technique for building the next generation optical Internet. An offset-time based scheme has recently been proposed in order to provide quality-of-service (QoS) in OBS networks. Unfortunately, the proposed service differentiation has several problems. The aim of this paper is to address these problems and introduce the concept of proportional QoS into this OBS paradigm. An intentional dropping scheme is proposed so as to give a controllable burst loss probability for different service classes. In order to achieve flexible packet delay differentiation, we extend the well-known waited-time-priority (WTP) scheduler to form a burst assembling scheme. Simulations are conducted to evaluate the performance of our proportional QoS provisioning within OBS networks in terms of burst loss probability and packet delay.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115118974","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965533
A. B. Mackenzie, S. Wicker
Game theory is a set of tools developed to model interactions between agents with conflicting interests, and is thus well-suited to address some problems in communications systems. We present some of the basic concepts of game theory and show why it is an appropriate tool for analyzing some communication problems and providing insights into how communication systems should be designed. We then provided a detailed example in which game theory is applied to the power control problem in a CDMA-like system.
{"title":"Game theory in communications: motivation, explanation, and application to power control","authors":"A. B. Mackenzie, S. Wicker","doi":"10.1109/GLOCOM.2001.965533","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965533","url":null,"abstract":"Game theory is a set of tools developed to model interactions between agents with conflicting interests, and is thus well-suited to address some problems in communications systems. We present some of the basic concepts of game theory and show why it is an appropriate tool for analyzing some communication problems and providing insights into how communication systems should be designed. We then provided a detailed example in which game theory is applied to the power control problem in a CDMA-like system.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123109521","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965901
C. Casetti, R. Cigno, M. Mellia, M. Munafò, Z. Zsóka
This paper addresses the problem of evaluating routing algorithms via simulation in packet-switched networks when elastic traffic is involved. It highlights some deficiencies of classical approaches that fail to capture both the complex interactions of connections traversing multiple bottlenecks and common user behaviors. The paper describes an approach devised to overcome these limitations which is particularly suited for the evaluation of routing algorithms in presence of best-effort traffic. The simulation results presented offer a deeper insight into well-known routing algorithms. Through this analysis it is clear that quantitative and also qualitative behaviors of dynamic routing algorithms based on traffic measurements may be fairly different depending on the nature of the traffic loading the network, as well as depending on its interactions with the network parameters and behavior.
{"title":"A realistic model to evaluate routing algorithms in the Internet","authors":"C. Casetti, R. Cigno, M. Mellia, M. Munafò, Z. Zsóka","doi":"10.1109/GLOCOM.2001.965901","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965901","url":null,"abstract":"This paper addresses the problem of evaluating routing algorithms via simulation in packet-switched networks when elastic traffic is involved. It highlights some deficiencies of classical approaches that fail to capture both the complex interactions of connections traversing multiple bottlenecks and common user behaviors. The paper describes an approach devised to overcome these limitations which is particularly suited for the evaluation of routing algorithms in presence of best-effort traffic. The simulation results presented offer a deeper insight into well-known routing algorithms. Through this analysis it is clear that quantitative and also qualitative behaviors of dynamic routing algorithms based on traffic measurements may be fairly different depending on the nature of the traffic loading the network, as well as depending on its interactions with the network parameters and behavior.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116896360","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965631
Jun Tan, Gordon L. Stüber
An analytical model for the extrinsic information of iterative max-log-MAP decoding of turbo codes is established based on a maximum probability approximation. The extrinsic information can be expressed as a Gaussian random variable with a mean and variance that are linear combinations of the received symbols. An important measure, called the effective weight, which is related to the pairwise error probability, is defined to explain the iterative decoding effect on a given code sequence. The evaluation of the pairwise error probability performance through decoder iterations can be calculated based on this model. The proposed approach can serve as a tool for the analysis of iterative max-log-MAP decoding.
{"title":"Analysis of iterative decoding of turbo codes","authors":"Jun Tan, Gordon L. Stüber","doi":"10.1109/GLOCOM.2001.965631","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965631","url":null,"abstract":"An analytical model for the extrinsic information of iterative max-log-MAP decoding of turbo codes is established based on a maximum probability approximation. The extrinsic information can be expressed as a Gaussian random variable with a mean and variance that are linear combinations of the received symbols. An important measure, called the effective weight, which is related to the pairwise error probability, is defined to explain the iterative decoding effect on a given code sequence. The evaluation of the pairwise error probability performance through decoder iterations can be calculated based on this model. The proposed approach can serve as a tool for the analysis of iterative max-log-MAP decoding.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116991510","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965554
H. Sari, F. Vanhaverbeke, M. Moeneclaey
We present a new encoded signaling concept which consists of transmitting an additional data rate of 50 % to the original data rate that is determined by the channel bandwidth, the modulation scheme, and other physical-layer functions of the transmission system. This is accomplished by overlaying an encoded version (using a rate 1/2 code with Hamming distance 4) of N/2 excess symbols to each block of N primary symbols. The resulting interference between primary and excess symbols is handled using a joint symbol detection technique with low complexity for N=8 and N=10. Our analysis shows that the transmission of the excess data rate involves an asymptotic gain in SNR of 0.8 dB as compared to conventional BPSK or QPSK signaling. Our simulation results indicate that this gain is noticeable at bit error rate (BER) values below about 10/sup -7/.
{"title":"An excess signaling technique with coding, signal superposition, and joint detection","authors":"H. Sari, F. Vanhaverbeke, M. Moeneclaey","doi":"10.1109/GLOCOM.2001.965554","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965554","url":null,"abstract":"We present a new encoded signaling concept which consists of transmitting an additional data rate of 50 % to the original data rate that is determined by the channel bandwidth, the modulation scheme, and other physical-layer functions of the transmission system. This is accomplished by overlaying an encoded version (using a rate 1/2 code with Hamming distance 4) of N/2 excess symbols to each block of N primary symbols. The resulting interference between primary and excess symbols is handled using a joint symbol detection technique with low complexity for N=8 and N=10. Our analysis shows that the transmission of the excess data rate involves an asymptotic gain in SNR of 0.8 dB as compared to conventional BPSK or QPSK signaling. Our simulation results indicate that this gain is noticeable at bit error rate (BER) values below about 10/sup -7/.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127324169","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965157
M. O. Damen, N. Beaulieu
The algebraic properties of two new space-time block codes over M transmitter antennas and T symbol periods are examined. The first code transmits at a rate of 2 symbols per channel use and has a transmit diversity of 2 over all 4-dimensional constellations carved from Z[i]/sup 4/ for M=T=2. From this code, we construct a space-time block code for M=T=3 which transmits at a rate of 4/3 symbols per channel use and has a transmit diversity of 3. We give upper and lower bounds to the achieved coding gains and prove that irrational numbers that are poorly approximated by rational numbers are particularly useful to enhance the coding gains of our schemes.
{"title":"Investigation of two high-rate algebraic space-time codes","authors":"M. O. Damen, N. Beaulieu","doi":"10.1109/GLOCOM.2001.965157","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965157","url":null,"abstract":"The algebraic properties of two new space-time block codes over M transmitter antennas and T symbol periods are examined. The first code transmits at a rate of 2 symbols per channel use and has a transmit diversity of 2 over all 4-dimensional constellations carved from Z[i]/sup 4/ for M=T=2. From this code, we construct a space-time block code for M=T=3 which transmits at a rate of 4/3 symbols per channel use and has a transmit diversity of 3. We give upper and lower bounds to the achieved coding gains and prove that irrational numbers that are poorly approximated by rational numbers are particularly useful to enhance the coding gains of our schemes.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127324788","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965517
W. Zha, S. Blostein
Successive interference cancellation (SIC) is a low-complexity multiuser detection method for DS/CDMA systems. If the channel is AWGN or slowly varying, averaging the channel amplitude estimates over multiple bits can greatly improve performance. However, the error propagation associated with a hard-limiter decision rule prevents SIC from achieving the performance improvement from averaging. We propose a new soft-decision rule to be used with amplitude averaging, which combines linear and hard decision rules. A performance within 0.4 dB of the single-user bound is obtained. We also made the above soft-decision SIC robust to time delay errors.
{"title":"Soft-decision successive interference cancellation CDMA receiver with amplitude averaging and robust to timing errors","authors":"W. Zha, S. Blostein","doi":"10.1109/GLOCOM.2001.965517","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965517","url":null,"abstract":"Successive interference cancellation (SIC) is a low-complexity multiuser detection method for DS/CDMA systems. If the channel is AWGN or slowly varying, averaging the channel amplitude estimates over multiple bits can greatly improve performance. However, the error propagation associated with a hard-limiter decision rule prevents SIC from achieving the performance improvement from averaging. We propose a new soft-decision rule to be used with amplitude averaging, which combines linear and hard decision rules. A performance within 0.4 dB of the single-user bound is obtained. We also made the above soft-decision SIC robust to time delay errors.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127449744","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965899
Seunghyun Oh, Jong-Suk Ahn
This paper proposes a data structure to perform forwarding lookups at gigabit speed by condensing the routing table of backbone routers into cache, thus eliminating slow memory accesses. The proposed structure bases on the conventional trie, known to be good for partial string searches. For the longest IP matching lookups, each level denotes a segment of IP address, and a node has multiple links each of which represents one combination of the address segment assigned to that level. When a given IP address reaches the dead-end node by following the links matching the IP address segment-by-segment, the node points the routing entry for forwarding the packet. For size reduction, the trie compresses pointers of child's locations and routing entries as a bit array where a single bit encodes a pointer. So, we call the proposed structure bit-map (BM) trie. For better performance, the BM trie jumps to the appropriate node at the middle level rather than starts from the root node. The experiments show that it compacts backbone routers' tables into 512 Kbyte cache and accomplishes around 2.4 million lookups per second on Pentium II processor.
{"title":"Bit-map trie: a data structure for fast forwarding lookups","authors":"Seunghyun Oh, Jong-Suk Ahn","doi":"10.1109/GLOCOM.2001.965899","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965899","url":null,"abstract":"This paper proposes a data structure to perform forwarding lookups at gigabit speed by condensing the routing table of backbone routers into cache, thus eliminating slow memory accesses. The proposed structure bases on the conventional trie, known to be good for partial string searches. For the longest IP matching lookups, each level denotes a segment of IP address, and a node has multiple links each of which represents one combination of the address segment assigned to that level. When a given IP address reaches the dead-end node by following the links matching the IP address segment-by-segment, the node points the routing entry for forwarding the packet. For size reduction, the trie compresses pointers of child's locations and routing entries as a bit array where a single bit encodes a pointer. So, we call the proposed structure bit-map (BM) trie. For better performance, the BM trie jumps to the appropriate node at the middle level rather than starts from the root node. The experiments show that it compacts backbone routers' tables into 512 Kbyte cache and accomplishes around 2.4 million lookups per second on Pentium II processor.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124872731","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965836
Jun Zheng, H. Mouftah
This paper studies distributed lightpath control in wavelength-routed WDM networks. We propose to introduce a destination-routing mechanism for lightpath establishment, which uses global network state information for wavelength routing and allows the destination node of a lightpath to decide the route. The purpose is to use the most recent network state information to make a routing decision so that wavelength reservation failures can be minimized. Meanwhile, we also consider connection restoration in the occurrence of a link failure and introduce a destination-initiating mechanism that allows the destination node of a broken connection to initiate a connection restoration process. The purpose is to reduce the connection restoration time so that a backup path can be provisioned rapidly. Based on both mechanisms, we further propose an efficient distributed control protocol for lightpath establishment and restoration. The paper explicitly describes the major procedures of the protocol, discusses its significant properties, and evaluates its performance in terms of the request blocking probability, and the connection setup or restoration time.
{"title":"Distributed lightpath control based on destination routing for wavelength-routed WDM networks","authors":"Jun Zheng, H. Mouftah","doi":"10.1109/GLOCOM.2001.965836","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965836","url":null,"abstract":"This paper studies distributed lightpath control in wavelength-routed WDM networks. We propose to introduce a destination-routing mechanism for lightpath establishment, which uses global network state information for wavelength routing and allows the destination node of a lightpath to decide the route. The purpose is to use the most recent network state information to make a routing decision so that wavelength reservation failures can be minimized. Meanwhile, we also consider connection restoration in the occurrence of a link failure and introduce a destination-initiating mechanism that allows the destination node of a broken connection to initiate a connection restoration process. The purpose is to reduce the connection restoration time so that a backup path can be provisioned rapidly. Based on both mechanisms, we further propose an efficient distributed control protocol for lightpath establishment and restoration. The paper explicitly describes the major procedures of the protocol, discusses its significant properties, and evaluates its performance in terms of the request blocking probability, and the connection setup or restoration time.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124896523","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.966348
D. Wiegandt, C. Nassar
WLAN (wireless local area networks) have emerged as a powerful architecture capable of meeting the needs of next generation broadband wireless communications. The IEEE 802.11a 5 GHz WLAN standard employs OFDM in its physical layer. This paper demonstrates that small changes in this OFDM scheme lead to notable improvements in probability of error performances. Calling the modified WLAN system carrier-interferometry WLAN (or CI-WLAN), we show that in office buildings, at a bit error rate of 10/sup -3/, CI-WLAN offers a 3 dB performance gain over the 802.11a 5 GHz WLAN.
{"title":"High-performance 802.11a wireless LAN via carrier-interferometry orthogonal frequency division multiplexing at 5 GHz","authors":"D. Wiegandt, C. Nassar","doi":"10.1109/GLOCOM.2001.966348","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.966348","url":null,"abstract":"WLAN (wireless local area networks) have emerged as a powerful architecture capable of meeting the needs of next generation broadband wireless communications. The IEEE 802.11a 5 GHz WLAN standard employs OFDM in its physical layer. This paper demonstrates that small changes in this OFDM scheme lead to notable improvements in probability of error performances. Calling the modified WLAN system carrier-interferometry WLAN (or CI-WLAN), we show that in office buildings, at a bit error rate of 10/sup -3/, CI-WLAN offers a 3 dB performance gain over the 802.11a 5 GHz WLAN.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125017035","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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