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Papers by Le Ngoc
IEEE Journal on Selected Areas in Communications, 2001
The performance of a priority-based dynamic capacity allocation suitable for wireless ATM systems... more The performance of a priority-based dynamic capacity allocation suitable for wireless ATM systems is presented. The scheduling of ATM cell transmission in each uplink TDMA frame is based on a priority scheme with priority given to real-time traffic over nonreal-time traffic. Real-time traffic exceeding the uplink capacity is lost while nonreal-time traffic that cannot be served is stored in a first-in first-out (FIFO) queue. An analytical model is developed to evaluate the cell loss ratio (CLR) of both real-time and nonreal-time traffic. Aggregate voice, video, and data traffic is modeled by three two-state Markov-modulated Poisson processes (MMPPs). Analytical results for different system capacities and various traffic loads and scenarios are discussed. Simulation results with on-off sources and approximating MMPP sources are also presented
The paper presents a study on the use of Markov-modulated Poisson processes (MMPPs) in modeling a... more The paper presents a study on the use of Markov-modulated Poisson processes (MMPPs) in modeling aggregate ATM traffic in order to evaluate the queueing performance. Performance of various techniques for matching a 2-state MMPP to a superposition of on-off sources is compared. The applicability of the 2-state MMPP and its corresponding parameter matching techniques to model an arbitrary aggregate ATM traffic in evaluating its queueing performance are examined by simulation. A refined matching technique for a 2-state MMPP model is proposed. A procedure to estimate the four parameters of a 2-state MMPP from the measured arrivals suitable for the moment-based matching technique is presented. Test cases are given to illustrate the accuracy of the proposed estimation procedure. An approximation for the survivor function is derived
Abstract This paper presents a tight upper bound on the bit error performance of coded modulation... more Abstract This paper presents a tight upper bound on the bit error performance of coded modulation schemes in Rayleigh fading channels. Upper and lower bounds on the pairwise error probability are first derived. The upper bound is then expressed in a product form to be used with the transfer function bounding technique. This upper bound has the same simplicity as the union-Chernoff bound while providing closer results to the exact expression. Examples for the case of four-state and eight-state TCM 8PSK schemes are ...
IEEE Transactions on Computers, 1997
A new cellular structure for a versatile Reed-Solomon (RS) decoder is introduced based on time do... more A new cellular structure for a versatile Reed-Solomon (RS) decoder is introduced based on time domain decoding algorithm. The time domain decoding algorithm is restructured to be suitable for introducing the cellular structure. The main advantages of this structure are its versatility and very simple cellular structure. By versatile decoder we mean a decoder that can be programmed to decode any (n, k) RS code defined in Galois field 2m with a fixed block length n and a fixed symbol size m. This decoder can correct both errors and erasures for any message length k. The introduced decoder is cellular and has a very simple structure and hence it is suitable for VLSI designs
IEEE Communications Magazine, 2003
Ngành: Triết học Chuyên ngành: Tôn giáo học Mã số: 60 22 90 (Ban hành kèm theo Quyết định số 4042... more Ngành: Triết học Chuyên ngành: Tôn giáo học Mã số: 60 22 90 (Ban hành kèm theo Quyết định số 4042/SĐH, ngày 26 tháng 10 năm 2007 của Giám đốc Đại học Quốc gia Hà Nội) I. MỤC TIÊU ĐÀO TẠO -Về kiến thức: Cung cấp cho học viên những kiến thức cơ bản, hệ thống, đặc biệt là quan điểm của chủ nghĩa Mác-Lênin, Đảng Cộng sản Việt Nam, tư tưởng Hồ Chí Minh về tôn giáo làm cơ sở để tiếp cận những vấn đề chuyên môn sâu thuộc lĩnh vực lí luận, lịch sử và vai trò của tôn giáo; Giúp cho học viên nắm được những
IEEE Journal on Selected Areas in Communications, 2001
The performance of a priority-based dynamic capacity allocation suitable for wireless ATM systems... more The performance of a priority-based dynamic capacity allocation suitable for wireless ATM systems is presented. The scheduling of ATM cell transmission in each uplink TDMA frame is based on a priority scheme with priority given to real-time traffic over nonreal-time traffic. Real-time traffic exceeding the uplink capacity is lost while nonreal-time traffic that cannot be served is stored in a first-in first-out (FIFO) queue. An analytical model is developed to evaluate the cell loss ratio (CLR) of both real-time and nonreal-time traffic. Aggregate voice, video, and data traffic is modeled by three two-state Markov-modulated Poisson processes (MMPPs). Analytical results for different system capacities and various traffic loads and scenarios are discussed. Simulation results with on-off sources and approximating MMPP sources are also presented
The paper presents a study on the use of Markov-modulated Poisson processes (MMPPs) in modeling a... more The paper presents a study on the use of Markov-modulated Poisson processes (MMPPs) in modeling aggregate ATM traffic in order to evaluate the queueing performance. Performance of various techniques for matching a 2-state MMPP to a superposition of on-off sources is compared. The applicability of the 2-state MMPP and its corresponding parameter matching techniques to model an arbitrary aggregate ATM traffic in evaluating its queueing performance are examined by simulation. A refined matching technique for a 2-state MMPP model is proposed. A procedure to estimate the four parameters of a 2-state MMPP from the measured arrivals suitable for the moment-based matching technique is presented. Test cases are given to illustrate the accuracy of the proposed estimation procedure. An approximation for the survivor function is derived
Abstract This paper presents a tight upper bound on the bit error performance of coded modulation... more Abstract This paper presents a tight upper bound on the bit error performance of coded modulation schemes in Rayleigh fading channels. Upper and lower bounds on the pairwise error probability are first derived. The upper bound is then expressed in a product form to be used with the transfer function bounding technique. This upper bound has the same simplicity as the union-Chernoff bound while providing closer results to the exact expression. Examples for the case of four-state and eight-state TCM 8PSK schemes are ...
IEEE Transactions on Computers, 1997
A new cellular structure for a versatile Reed-Solomon (RS) decoder is introduced based on time do... more A new cellular structure for a versatile Reed-Solomon (RS) decoder is introduced based on time domain decoding algorithm. The time domain decoding algorithm is restructured to be suitable for introducing the cellular structure. The main advantages of this structure are its versatility and very simple cellular structure. By versatile decoder we mean a decoder that can be programmed to decode any (n, k) RS code defined in Galois field 2m with a fixed block length n and a fixed symbol size m. This decoder can correct both errors and erasures for any message length k. The introduced decoder is cellular and has a very simple structure and hence it is suitable for VLSI designs
IEEE Communications Magazine, 2003
Ngành: Triết học Chuyên ngành: Tôn giáo học Mã số: 60 22 90 (Ban hành kèm theo Quyết định số 4042... more Ngành: Triết học Chuyên ngành: Tôn giáo học Mã số: 60 22 90 (Ban hành kèm theo Quyết định số 4042/SĐH, ngày 26 tháng 10 năm 2007 của Giám đốc Đại học Quốc gia Hà Nội) I. MỤC TIÊU ĐÀO TẠO -Về kiến thức: Cung cấp cho học viên những kiến thức cơ bản, hệ thống, đặc biệt là quan điểm của chủ nghĩa Mác-Lênin, Đảng Cộng sản Việt Nam, tư tưởng Hồ Chí Minh về tôn giáo làm cơ sở để tiếp cận những vấn đề chuyên môn sâu thuộc lĩnh vực lí luận, lịch sử và vai trò của tôn giáo; Giúp cho học viên nắm được những