Patent ID: 8169997
Filing Date: 2012-05-01
Classification: H04W

Abstract:
1. A communication system comprising: a base station having a processor that processes a physical layer using a given data format; and terminal devices each using an up-link line allocated by the base station, wherein the base station and each terminal device communicate with each other by an orthogonal frequency division multiplexing method, and by using a frame comprising a first subframe for a down-link line, on which a preamble signal and a broadcast signal including down-link allocation information and up-link allocation information are provided, and a second subframe for the up-link line, on which a bandwidth request signal and an up-link data burst are provided, wherein the base station comprises: a transmitter which sends out periodically a preamble signal including a synchronous signal with which a terminal device synchronizes, and sends out a vacant discrete connection identifier, which identifies a vacant up-link line through which the terminal device sends data to the base station when the base station receives an up-link line request from the terminal device, and each of the terminal devices comprises: a storage which is synchronized with the preamble signal from the base station to store a discrete connection identifier which is being used and is provided in the broadcast signal; a transmitter which sends an up-link line request code corresponding to a device number of the terminal device, as the up-link line request to the base station; and a detector which recognizes the up-link line allocation information sent from the base station, as a reply to the up-link line request, to distinguish the stored discrete connection identifier from a discrete connection identifier added by the up-link line allocation information received from the base station in a predetermined number of frames later and to determine the added discrete connection identifier distinguished from the stored discrete connection identifier, as aimed at the terminal device, and wherein the transmitter of the terminal device sends out data by using a line burst area designated by the added discrete connection identifier, and retransmits an up-link line request when the terminal device detector fails to recognize any connection identifier aimed at the terminal device.