Channel allocation schemes

About: Channel allocation schemes is a research topic. Over the lifetime, 10656 publications have been published within this topic receiving 182117 citations.

Cognitive radio spectrum allocation using evolutionary algorithms

Abstract: Cognitive radio has been regarded as a promising technology to improve spectrum utilization significantly. In this letter, spectrum allocation model is presented firstly, and then spectrum allocation methods based on genetic algorithm (GA), quantum genetic algorithm (QGA), and particle swarm optimization (PSO), are proposed. To decrease the search space we propose a mapping process between the channel assignment matrix and the chromosome of GA, QGA, and the position of the particle of PSO, respectively, based on the characteristics of the channel availability matrix and the interference constraints. Results show that our proposed methods greatly outperform the commonly used color sensitive graph coloring algorithm.

Handover and dynamic channel allocation techniques in mobile cellular networks

Abstract: This paper deals with an efficient dynamic channel allocation (DCA) technique applicable to terrestrial mobile cellular networks. A channel (or resource) is a fixed frequency bandwidth (FDMA), a specific time-slot within a frame (TDMA), or a particular code (CDMA), depending on the multiple access technique used. A cost function has been defined by which the optimum channel to be assigned on demand can be selected. In addition, a suitable mobility model has been derived to determine the effects of handovers on network performance. The performance of the proposed DCA technique has been derived by computer simulations in terms of call blocking and handover failure probabilities. Comparisons with the classical fixed channel allocation (FCA) technique and other dynamic allocation algorithms recently proposed in the literature have been carried out to validate the proposed technique. >

Dynamic Wavelength and Bandwidth Allocation in Hybrid TDM/WDM EPON Networks

Abstract: We discuss a wavelength-division-multiplexed-based passive-optical-network (PON) architecture that allows for incremental upgrade from single-channel time-division multiple-access PONs in order to provide higher bandwidth in the access network. Various dynamic-wavelength and bandwidth-allocation algorithms (DWBAs) for wave-division multiplexed PON are presented; they exploit both interchannel and intrachannel statistical multiplexing in order to achieve better performance, especially when the load on various channels is not symmetric. Three variants of the DWBA are presented, and their performance is compared. While the first variant incurs larger idle times (and, hence, poor performance), the other two algorithms achieve better but different performance with critical dissimilarities. Our analysis also focuses on the fair assignment of excessive bandwidth in the upstream direction to highly loaded optical network units. We compare the performance of DWBA to another algorithm that relies on static-channel allocation. Furthermore, a study is presented wherein the number of wavelengths increases, and a comparison with interleaved polling with adaptive cycle time is shown. We use extensive simulations throughout this paper

Satellite Systems for Personal and Broadband Communications

Abstract: I. Basics.- 1. Introduction.- 1.1 Mobile and Personal Satellite Communications.- 1.1.1 Applications of Mobile Satellite Communications.- 1.1.2 Personal Satellite Communications.- 1.1.3 UMTS, IMT-2000.- 1.2 Broadband Multimedia Satellite Communications.- 1.3 Frequency Bands.- 1.4 Key Aspects of Satellite Communication Systems.- 2. Satellite Orbits, Constellations, and System Concepts.- 2.1 Satellite Orbits.- 2.1.1 Elliptical and Circular Orbits.- 2.1.2 Satellite Velocity and Orbit Period.- 2.1.3 Orientation of the Orbit Plane.- 2.1.4 Typical Circular Orbits.- 2.1.5 Orbit Perturbations.- 2.1.6 Ground Tracks.- 2.2 Satellite - Earth Geometry.- 2.2.1 Geometric Relations between Satellite and Earth Terminal.- 2.2.2 Coverage Area.- 2.3 Satellite Constellations.- 2.3.1 Inclined Walker Constellations.- 2.3.2 Polar Constellations.- 2.3.3 Asynchronous Polar Constellations.- 2.4 GEO System Concept.- 2.4.1 Inmarsat-3.- 2.4.2 EAST (Euro African Satellite Telecommunications).- 2.5 LEO System Concept.- 2.5.1 Globalstar.- 2.5.2 Intersatellite Links and On-Board Processing.- 2.5.3 Iridium.- 2.6 MEO System Concept.- 2.6.1 ICO.- 2.7 Satellite Launches.- 3. Signal Propagation and Link Budget.- 3.1 Satellite Link Budget.- 3.1.1 Antenna Characteristics.- 3.1.2 Free Space Loss and Received Power.- 3.1.3 Link Budget.- 3.1.4 Spot Beam Concept.- 3.2 Peculiarities of Satellite Links.- 3.2.1 Dependence on Elevation.- 3.2.2 Time Dependence of Satellite Links.- 3.2.3 Faraday Rotation.- 3.3 Signal Shadowing and Multipath Fading.- 3.3.1 Narrowband Model for the Land Mobile Satellite Channel.- 3.3.2 Satellite Channels at Higher Frequencies.- 3.3.3 Wideband Model for the Land Mobile Satellite Channel.- 3.4 Link Availability and Satellite Diversity.- 3.4.1 Concept of Satellite Diversity.- 3.4.2 Correlation of Channels.- 3.4.3 Link Availability and Satellite Diversity Service Area.- 3.5 System Implications.- 4. Signal Transmission.- 4.1 Speech Coding.- 4.1.1 Quality of Coded Speech.- 4.1.2 Overview of Speech Coding Schemes.- 4.2 Modulation.- 4.2.1 Modulation Schemes for Mobile Satellite Communications.- 4.2.2 Bandwidth Requirement of Modulated Signals.- 4.2.3 Bit Error Rate in the Gaussian Channel.- 4.2.4 Bit Error Rate in the Ricean and Rayleigh Fading Channel.- 4.3 Channel Coding (Forward Error Correction, FEC).- 4.3.1 Convolutional Coding.- 4.3.2 Block Coding.- 4.3.3 Error Protection with Cyclic Redundancy Check (CRC).- 4.3.4 RS Codes.- 4.3.5 Performance of Block Codes.- 4.3.6 Performance of Block Codes in Fading Channels.- 4.4 Automatic Repeat Request (ARQ).- 4.4.1 Stop-and-Wait ARQ.- 4.4.2 Go-Back-N ARQ.- 4.4.3 Selective-Repeat ARQ.- 4.5 Typical Error Control Schemes in Mobile Satellite Communications.- II. Satellite Systems for Mobile/Personal Communications.- 5. Multiple Access.- 5.1 Duplexing.- 5.1.1 Frequency-Division Duplexing (FDD).- 5.1.2 Time-Division Duplexing (TDD).- 5.2 Multiplexing.- 5.3 Multiple Access.- 5.4 Slotted Aloha Multiple Access.- 5.4.1 The Principle of Slotted Aloha.- 5.4.2 Throughput of Slotted Aloha.- 5.4.3 Mean Transmission Delay for Slotted Aloha.- 5.4.4 Pure Aloha Multiple Access.- 5.5 Frequency-Division Multiple Access, FDMA.- 5.5.1 Adjacent Channel Interference.- 5.5.2 Required Bandwidth for FDMA.- 5.5.3 Intermodulation.- 5.5.4 Pros and Cons of FDMA.- 5.6 Time-Division Multiple Access, TDMA.- 5.6.1 Bandwidth Demand and Efficiency of TDMA.- 5.6.2 Burst Synchronization in the Receiving Satellite.- 5.6.3 Slot Synchronization in the Transmitting TDMA Terminals.- 5.6.4 Pros and Cons of TDMA.- 5.7 Code-Division Multiple Access, CDMA.- 5.8 Direct-Sequence CDMA (DS-CDMA).- 5.8.1 Generation and Characteristics of Signature Sequences.- 5.8.2 Investigation of Asynchronous DS-CDMA in the Time Domain.- 5.8.3 Investigation of Asynchronous DS-CDMA in the Frequency Domain.- 5.8.4 Multi-Frequency CDMA, MF-CDMA.- 5.8.5 Qualcomm Return Link CDMA (Globalstar).- 5.8.6 Synchronous Orthogonal DS-CDMA with Coherent Detection.- 5.9 CDMA Receivers.- 5.9.1 PN Code Synchronization in the CDMA Receiver.- 5.9.2 Rake Receiver.- 5.9.3 CDMA Multiuser Detection.- 5.10 Characteristics of CDMA.- 5.11 CDMA for the Satellite UMTS Air Interface.- 5.11.1 The ESA Wideband CDMA Scheme.- 5.11.2 The ESA Wideband Hybrid CDMA/TDMA Scheme.- 6. Cellular Satellite Systems.- 6.1 Introduction.- 6.1.1 Concept of the Hexagonal Radio Cell Pattern.- 6.1.2 Cell Cluster and Frequency Reuse.- 6.2 Co-Channel Interference in the Uplink.- 6.2.1 Co-Channel Interference for FDMA and TDMA Uplinks.- 6.2.2 Co-Channel Interference for an Asynchronous DS-CDMA Uplink.- 6.3 Co-Channel Interference in the Downlink.- 6.3.1 Co-Channel Interference for FDMA and TDMA Downlinks.- 6.3.2 Co-Channel Interference for CDMA Downlinks.- 6.4 Bandwidth Demand and Traffic Capacity of Cellular Satellite Networks.- 6.4.1 Total System Bandwidth.- 6.4.2 Traffic Capacity per Radio Cell.- 6.4.3 Traffic Capacity of the System.- 6.4.4 Required User Link Capacity of a Satellite.- 6.4.5 Overall Network Capacity Considerations.- 7. Network Aspects.- 7.1 Architecture of Satellite Systems for Mobile/Personal Communications.- 7.2 Network Control.- 7.2.1 Tasks of Network Control.- 7.2.2 Signaling Channels of the Air Interface.- 7.3 Mobility Management.- 7.3.1 Service Area of a Gateway Station.- 7.3.2 Location Area.- 7.3.3 Registration and Location Update.- 7.4 Paging.- 7.5 Call Control.- 7.5.1 Setup of a Mobile Originating Call.- 7.5.2 Setup of a Mobile Terminating Call.- 7.6 Dynamic Channel Allocation.- 7.6.1 C/I-Based DCA.- 7.6.2 DCA Using a Cost Function.- 7.7 Handover.- 7.7.1 Handover Decision.- 7.7.2 Handover Procedure.- 7.7.3 Channel Allocation at Handover.- 7.8 Call Completion Probability.- 7.9 Routing.- 7.9.1 Routing in LEO/MEO Satellite Networks.- 7.9.2 Off-Line Dynamic ISL Routing Concept.- 7.9.3 On-line Adaptive ISL Routing.- 7.10 Integration of Terrestrial and Satellite Mobile Networks.- 8. Satellite Technology.- 8.1 Satellite Subsystems.- 8.2 Antenna Technology.- 8.2.1 GEO Antennas for Mobile Links with Spot Beams.- 8.2.2 LEO/MEO Antennas.- 8.3 Payload Architecture.- 9. Regulatory, Organizational, and Financial Aspects.- 9.1 Allocation of Frequency Bands.- 9.2 Licensing/Regulation.- 9.2.1 Granting a System License.- 9.2.2 Licensing in the USA.- 9.2.3 Licensing in Europe.- 9.2.4 Common Use of Frequency Bands by Several Systems.- 9.2.5 Global Licensing and Political Aspects.- 9.3 Financing and Marketing of S-PCN Systems.- 9.4 Operation of S-PCN Systems.- III. Satellite Systems for Broadband Multimedia Communicat ions.- 10. Multimedia Communications in Satellite Systems.- 10.1 Types of Broadband Communication Networks.- 10.1.1 Traditional Circuit-Switched Networks and the Packet-Switched Internet.- 10.1.2 New Multimedia Satellite Systems Using New Satellite Orbits.- 10.2 Multimedia Services and Traffic Characterization.- 10.2.1 Video Traffic and MPEG Coding.- 10.2.2 Self-Similar Traffic.- 10.3 ATM-Based Communication in Satellite Systems.- 10.3.1 Principles of ATM.- 10.3.2 Implications for ATM-Based Satellite Networks.- 10.4 Internet Services via Satellite Systems.- 10.4.1 Principles of TCP/IP.- 10.4.2 Internet Protocol (IP).- 10.4.3 Transport Control Protocol (TCP).- 10.4.4 TCP/IP in the Satellite Environment.- 10.4.5 IP over ATM in the Satellite Environment.- 11. ATM-Based Satellite Networks.- 11.1 System Architecture.- 11.2 Services.- 11.3 Protocol Architecture.- 11.4 ATM Resource Management.- 11.4.1 Connection Admission Control and Usage Parameter Control.- 11.4.2 Congestion Control, Traffic Shaping, and Flow Control.- 11.5 Multiple Access for ATM Satellite Systems.- 11.5.1 TDMA-Based Multiple Access.- 11.5.2 CDMA-Based Multiple Access.- 11.6 Radio Resource Management.- 11.7 Error Control.- 12. Network Dimensioning.- 12.1 Spot Beam Capacity Dimensioning for GEO Systems.- 12.1.1 Motivation and Approach.- 12.1.2 Market Prediction.- 12.1.3 Generic Multiservice Source Traffic Model.- 12.1.4 Calculation of the Spot Beam Capacity Requirements.- 12.1.5 System Bandwidth Demand Calculation.- 12.1.6 Applied Spot Beam Capacity Dimensioning: A Case Study.- 12.2 ISL Capacity Dimensioning for LEO Systems.- 12.2.1 Topological Design of the ISL Network.- 12.2.2 ISL Routing Concept.- 12.2.3 Network Dimensioning.- 12.2.4 Numerical Example.- 12.2.5 Extensions of the Dimensioning Approach.- A. Satellite Spot Beams and Map Transformations.- A.1 Map Projections and Satellite Views.- A.2 Generation of Satellite Spot Beams.- B. Parameters of the Land Mobile Satellite Channel.- B.1 Narrowband Two-State Model at L Band.- B.2 Narrowband Two-State Model at EHF Band.- B.3 Wideband Model at L Band.- C. Existing and Planned Satellite Systems.- C.1 Survey of Satellite Systems.- C.2 ACeS (Asia Cellular Satellite).- C.3 Astrolink.- C.4 EuroSkyWay.- C.5 Globalstar.- C.6 ICO (Intermediate Circular Orbits).- C.7 Inmarsat-3/Inmarsat mini-M.- C.8 Iridium.- C.9 Orbcomm.- CIO SkyBridge.- C.11 Sky Station.- C.12 Spaceway.- C.13 Teledesic.- References.

Improved call set-up and spectrum sharing in radio communication on systems with dynamic channel allocation

Abstract: The call set-up technique of this invention is characterized by the use of channel information from both base station and subscriber terminal in determining the radio traffic channel upon which to set-up a new call. Communication between the base station and subscriber terminal is carried out on a signalling channel until the traffic channel is chosen. Calls are set-up so that they proceed on the radio channel which, of a set of channels under consideration by the subscriber terminal, contains the least amount of interference as measured at the subscriber terminal. The set of channels under consideration by the subscriber terminal is a subset of the entire set of channels allocated to the service. This subset is comprised of those channels having little interference, as measured by the base station, and which, additionally, are not reserved exclusively for stationary, fixed-allocation services in the geographic location of the base station. The call set-up technique thereby assures that calls proceed on channels containing little interference from the viewpoint of both base station and subscriber terminal. The technique also facilitates sharing of the radio spectrum with stationary, fixed-allocation services because there is no need to program each subscriber terminal to avoid the spectrum allocated to the fixed service.