{"title":"Wireless Local Area Network Performance in a Bluetooth Interference Environment","authors":"R. Noel, R. Baldwin, R. Raines, M. Temple","doi":"10.1142/S0219799504000180","DOIUrl":"https://doi.org/10.1142/S0219799504000180","url":null,"abstract":"Since IEEE 802.11 wireless local area networks (WLANs) and Bluetooth (BT) personal area networks both use the 2.4 GHz Industrial, Scientific, and Medical band, interference can occur when these networks are collocated. A WLAN station's clear channel assessment algorithm will declare a channel busy and induce transmission delays when sufficient energy from a BT signal is received. By assuming the BT's frequency hopped spread spectrum signal will not corrupt the direct sequence spread spectrum WLAN transmission, we isolate and characterize transmission delays due solely to BT interference. We develop expressions for throughput, delay, expected backoff interval, expected number of collisions, and other metrics of interest. In situations where numerous collisions occur between WLAN stations, BT-induced transmission delays reduce the probability of expensive WLAN collisions while increasing overall throughput and decreasing delay. An analytic model is developed to predict interference effects and is verified t...","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"150 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133907118","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}
R. Datta, A. K. Turuk, S. Ghose, Rajeev Kumar, I. Sengupta
{"title":"New Schemes for Connection Establishment in GMPLS Environment for WDM Networks","authors":"R. Datta, A. K. Turuk, S. Ghose, Rajeev Kumar, I. Sengupta","doi":"10.1142/S0219799504000234","DOIUrl":"https://doi.org/10.1142/S0219799504000234","url":null,"abstract":"Generalized Multi-Protocol Label Switching (GMPLS) is growing in popularity as a set of protocols for provisioning and managing core optical networks. In this paper, we present new schemes for provisioning lightpaths in WDM optical network. We first propose a path selection scheme required for deploying lightpaths in GMPLS environment. When a request for lightpath arrives at a source LSR, in GMPLS it is required to send request messages from an upstream LSR to the downstream LSR for setting up a lightpath. Therefore it is needed that an appropriate route be selected through the optical network for the requested lightpath. Keeping in mind its signaling characteristics we describe a path selection algorithm that can be built on GMPLS to enhance its performance. We next propose a path setup scheme for setting up the connection using the path selected with our earlier scheme. The lookahead approach of our path set up scheme enables it to work faster than existing GMPLS path setup protocols. We performed extensive simulation and found that the blocking probability of the WDM networks in GMPLS environment is lower when using our schemes than with the existing standard protocols.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127723933","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}
{"title":"Power and Bandwidth-Efficient Circular M-Ary APSK Schemes with Low PAPR","authors":"Thai Hoa Vo, T. Le-Ngoc","doi":"10.1142/S0219799504000192","DOIUrl":"https://doi.org/10.1142/S0219799504000192","url":null,"abstract":"This paper presents a class of circular M-ary Amplitude-Phase Shift Keying (APSK) signaling techniques with high bandwidth efficiency and low peak-to-average power ratio (PAPR) suitable for systems using nonlinear power amplifiers to achieve high power efficiency. For nonlinear amplification, good performance requires not only high squared minimum distance to average power ratio (DPR) but also low PAPR. A search algorithm for M-ary APSK schemes using circular constellations suitable for nonlinear amplification with minimum PAPR and maximum DPR is developed. Results for 8-, 16-, 32-, 64- and 128-APSK signalling schemes are presented. The effects of bandlimiting filter sharpness on the PAPR are examined and considered in the development. The analytical and simulation results show that this class of circular M-ary APSK signals outperforms the square and cross M-ary QAM schemes.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126038213","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}
{"title":"Evaluation of Dynamic Slot Allocation for Space-Division Multiple Access in a Smart Antenna System","authors":"Chih-Wei Chen, G. Okamoto","doi":"10.1142/S0219799504000179","DOIUrl":"https://doi.org/10.1142/S0219799504000179","url":null,"abstract":"In this paper we evaluate the performance of fixed-user-per-slot and dynamic slot allocation for a smart antenna system using Space-Division Multiple Access. Fixed-user-per-slot allocation is studied with the first-come first-served method for different beamforming algorithms and sorting techniques. Dynamic slot allocation is studied with the first fit and modified first fit (MFF) methods. MFF requires significantly less computational complexity to select sets of users for simultaneous transmission in a frequency band. It is found that sorting by input SNR does not affect the throughput rate, but sorting by data length sharply improves the throughput rate. The tradeoff between capacity and range of a smart antenna system is evaluated. The effect of multipath on system capacity is studied, with results showing that the throughput rate significantly increases when at least one multipath signal is present.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"2012 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127378651","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}
R. Inayat, R. Aibara, K. Nishimura, Takahiro Fujita, Y. Nomura, Kaori Maeda
{"title":"Realizing Fast Mobility and Multi-Homing Support in IP Wireless Access Networks","authors":"R. Inayat, R. Aibara, K. Nishimura, Takahiro Fujita, Y. Nomura, Kaori Maeda","doi":"10.1142/S0219799503000124","DOIUrl":"https://doi.org/10.1142/S0219799503000124","url":null,"abstract":"The work described in this paper proposes and evaluates an end-to-end communication approach in realizing terminal mobility in IP wireless access networks. The proposed network architecture also provides a solution to multi-homing in IPv4 and IPv6 networks. It concentrates on end-to-end abstraction and does not require any special service from the underlay network infrastructure. The multi-homing capability is used to achieve seamless handoff. Based on multi-homing we also propose and evaluate a handoff scheme that exploits the overlapping coverage area and speed of the mobile node between sub-networks. We describe the network architecture and show its mobility and multi-homing capability by prototype implementation and by performance evaluation. Our implementation does not have any significant bad performance impact on plain versions of IPv4 and IPv6. The evaluation of handoff scheme shows that packet loss and handoff latency can be reduced significantly even with the end-to-end design, depending upon th...","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127761958","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}
{"title":"Improving Goodput of the IEEE 802.11 MAC Protocol by Using Congestion Control Methods","authors":"S. Ci, H. Sharif, G. Noubir","doi":"10.1142/S021979950300015X","DOIUrl":"https://doi.org/10.1142/S021979950300015X","url":null,"abstract":"Fragmentation is proposed for mitigating the bad affects resulted from intermittent interferences and noises. However, the current fragmentation algorithm used in the IEEE 802.11 protocol only supports fixed fragment size. Since the wireless channel and the network load are time-varying, this fixed algorithm is obviously not optimal for the goodput performance. In this paper, we present and analyze two simple yet effective adaptive fragmentation algorithms for goodput enhancement. First, we study the analogies between the TCP protocol and MAC protocols in terms of their resource control methods. Next, we propose an adaptive approach based on the heuristics of congestion control schemes by dynamically varying the fragment size according to changes of wireless channel quality. Simulations have been conducted by using real channel measurements in a typical indoor environment, and results show that the proposed algorithms outperform the current fixed fragment scheme and can significantly improve the goodput performance up to seven times more than the fixed fragment scheme. Moreover, the proposed adaptive fragmentation algorithms introduce insignificant overhead and the implementation is very practical.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132323475","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}
{"title":"Terahertz Bandwidth Optical Comb Generation Using Optoelectronic Phase-Locked Loop","authors":"M. Bhattacharya, A. K. Saw, T. Chattopadhyay","doi":"10.1142/S0219799503000148","DOIUrl":"https://doi.org/10.1142/S0219799503000148","url":null,"abstract":"This paper proposes a THz bandwidth optical comb generation scheme by phase modulating two optical carriers simultaneously in an electrooptic overdriven phase modulator. The frequency difference between the two optical carriers is maintained constant by using an optoelectronic phase locked loop (OEPLL). It has been shown analytically that taking a microwave drive frequency of 25 GHz, 41 comb lines, lying within a power envelope of 20 dB, span over a frequency bandwidth of 1 THz with a comb line spacing of 25 GHz.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129965808","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}
M. Vera-Isasa, M. Sierra-Castañer, M. Sierra-Pérez
{"title":"Design of Circular Polarized Radial Line Slot Antennas","authors":"M. Vera-Isasa, M. Sierra-Castañer, M. Sierra-Pérez","doi":"10.1142/S0219799503000161","DOIUrl":"https://doi.org/10.1142/S0219799503000161","url":null,"abstract":"A systematic design process for circular polarized radial line slot antennas is presented herein. In order to obtain circular polarization a spiral slot arrangement is needed. Slot coupling determination to obtain a desired aperture illumination is also important. The unit radiation element is composed of two slots that are designed to optimize the copolar to crosspolar ratio and the position and length of all the slots in the array can be determined with this method. Although the suggested method is suitable for obtaining any high or medium gain antenna, a direct broadcast satellite (DBS) reception antanna design is proposed as an application example.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123202978","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}
{"title":"Wireless Access and Terminal Mobility in CORBA","authors":"K. Raatikainen","doi":"10.1142/S0219799503000112","DOIUrl":"https://doi.org/10.1142/S0219799503000112","url":null,"abstract":"The Object Management Group has recently published the Wireless Access and Terminal Mobility in CORBA standard — Wireless CORBA for short. The specification enables mobility transparency of objects on a mobile terminal through a mobile Interoperable Object Reference (mobile IOR). A GIOP tunneling protocol is used to handle handoffs between access bridges even when the access technology changes. The current standard supports TCP, UDP, WAP WDP and Bluetooth L2CAP transports. The mobility management is based on principles of the current GSM network. The CORBA ORB is, however, only involved in handoffs between bridging domains, whereas mobility inside a bridging domain is handled by Mobile IP and/or link level mechanisms. The Wireless CORBA specification also provides the basic means to discover and resolve initial object references in the home and visited domains.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121824381","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}
{"title":"Z-Domain Design of Space-Time Block Coding Single-Carrier Transmission over Frequency-Selective Fading Channels","authors":"Changjiang Xu, T. Le-Ngoc","doi":"10.1142/S0219799503000136","DOIUrl":"https://doi.org/10.1142/S0219799503000136","url":null,"abstract":"In this paper, we present a general z-domain design for STBC single-carrier transmission schemes with multiple transmit antennas over frequency-selective fading channels. Using z-transform approach, we develop the STBC single-carrier transmission transceiver structures and examine its performance gain. Low-complexity detection and/or equalization can be performed in the frequency domain.","PeriodicalId":185917,"journal":{"name":"Int. J. Wirel. Opt. Commun.","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126090590","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}