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.

Ofdm frequency reuse method in mobile communication system

Abstract: PROBLEM TO BE SOLVED: To provide a method for efficiently reusing a frequency in a mobile communication system using OFDM. SOLUTION: In the method for reusing orthogonal frequency division multiplexing frequency resources in the mobile communication system including a plurality of base stations communicating with a terminal in an orthogonal frequency division multiplexing frequency scheme, the orthogonal frequency division multiplexing frequency resources available in respective base stations 200-260 are divided into four or more groups. The method comprises: a process for setting each of the divided orthogonal frequency division multiplexing frequency resources to have a frequency reuse distance value which is equal or different for each of orthogonal frequency division multiplexing frequency resources; and a process for assigning the resources serially in order from the resource of the smallest frequency reuse distance value to the resource of the greatest frequency reuse distance value among the orthogonal frequency division multiplexing frequency resources divided in order from a nearby area of the base station to a long-distance area. COPYRIGHT: (C)2007,JPO&INPIT

Multiple access options for cellular based personal communications

Abstract: The possible evolution of time division multiple access (TDMA) by, e.g., introducing frequency hopping and/or adaptive channel allocation, is described. The possibilities of direct sequence (DS) code division multiple access (CDMA) are considered. The different multiple access methods are examined. In particular, the concept of hierarchical cell structures is emphasized. The capacity depends on both the cell capacity and the ability to support hierarchical cell structures.

System centric and user centric queueing models for IEEE 802.11 based wireless LANs

Abstract: We consider the following two views of an IEEE 802.11 based Wireless LAN: (i) as seen by the WLAN medium and (ii) as seen by a user. In the system centric view, we model the WLAN medium as a server that allocates its resources to users in a round Robin manner. This resource sharing model not only provides a simple model for the system, it also enables us to derive the channel service rate and the total delay incurred in transmitting a packet. For Poisson arrivals, the resource sharing model takes the form of an M/G/1/PS system with the mean delay being the same as that in an equivalent M/M/1 system. We then take a user centric view and model each user's queue as a separate G/G/1 queue. We derive the probability distributions for the different delay sources, i.e., random back-off time, random number of collisions and random number of successful transmissions from other users. This user centric model can provide insights into understanding access and queuing delays in 802.11 DCF. Finally, we discuss the utility of these models for functions such as capacity analysis, admission control and QoS enforcement.

System and method for dynamic channel allocation in a communication system using an orthogonal frequency division multiple access network

Abstract: A system and method for dynamically allocating channels in a wireless communication system including multiple sub-channels and multiple frame cells, each of the sub-channels being an assembly including a preset number of sub-frequency bands divided from an overall frequency band, the frame cells using each of the sub-channels as a basic transmission unit and having a frequency domain and a time domain occupied by the sub-channels. A mobile station transmits channel quality information of frame cells to an access point. An access router transmits channel allocation information about the multiple frame cells and sub-channels determined according to the received channel quality information to the access point, and the access point receives the channel allocation information about the multiple frame cells and sub-channels, compares the channel allocation information with newest channel quality information, and allocates a sub-channel of a frame cell selected according to the comparison to the mobile station.

Implementation of a bandwidth allocation scheme in a token-passing fieldbus network

Abstract: This paper presents a method for implementing a bandwidth allocation scheme on Profibus that operates on a token-passing discipline basis. In order to implement the bandwidth allocation scheme, this study incorporates the following additional functions to the fieldbus datalink layer (FDL) protocol of Profibus. First, the medium bandwidth of the network system is separated into both periodic and time-available intervals, and, second, node timers are synchronized over a local link. The validity of this bandwidth allocation scheme is determined using an experimental model of a network system. The results obtained from the experimental model show that the proposed scheme restricts the delay of both periodic and time-critical data to a pre-specified bound. The proposed bandwidth allocation scheme also fully utilized the bandwidth resource of the network system.