Apparatus and method for configuring a data channel for symmetric/asymmetric data transmission

#1. Field of the Invention

#This invention relates to telecommunications systems and, more particularly, to an apparatus and method for providing reduced length link setup signaling messages in a telecommunications system having a variable rate symmetric/asymmetric data channel.

#2. Prior Art

#A more complete understanding of the apparatus and method of the present invention may be had by referring to the following detailed description read in conjunction with the accompanying drawings wherein:

#FIG. 1 is a block diagram illustrating a telecommunications system which may be adapted to incorporate an embodiment in accordance with the present invention;

#FIG. 2A is a schematic block diagram showing portions of a transmitter/modulator for transmitting variable rate data on a reverse link in the system of FIG. 1 according to an embodiment of the present invention;

#The present invention embodies an apparatus and method for shortening the time and signal length required in the connection setup in a telecommunications system by configuring the signaling messages, when setting up the data transmission rates on the forward and reverse links for variable data transmission, such that if both forward and reverse links use the same rate configuration, i.e., the same setup parameters, only one rate configuration is encoded in the signaling message. Briefly, this improvement is achieved with the use of an ASYMMETRIC.sub.-- RATES bit field in the link setup request message. However, for a thorough understanding of the context and features of the apparatus and method for carrying out the invention the following description is presented.

#FIG. 1 illustrates a set of operating components in a telecommunications system 1 constructed in a manner suitable for the incorporation of an embodiment of the present invention. Telecommunications system 1 may be any telephone or wireless system for transmitting messages between two stations that can be adapted to exchange messages in accordance with the invention. The preferred embodiment is implemented in, and will be described in connection with, a celular phone system having base stations and mobile stations. The mobile stations may be in the form of cellular telephones, computers, and other such transceivers, which are used by a person or subscriber to communicate with one or more base stations operated by a service provider. As all forms of mobile stations may not be readily movable or portable, although for the most part they are, herein the mobile stations may also be referred to as personal stations. Accordingly, system 1 is shown as cellular and includes a mobile station 14 that communicates with an infrastructure that comprises a series of base stations 2, 4, 6, 8, and 10, disposed respectively in cells A-E and all connected to a system controller and switch 12. A subscriber to the cellular telephone service of system 1 may use mobile station 14 to make and receive phone calls over a radio interface, having forward and reverse links, 20 and 18, between station 14 and base station 8, as station 14 moves throughout the coverage area of the system. The base stations are connected to controller and switch 12 over conventional cellular phone connections, and controller and switch 12 is connected to a public switched telephone network (PSTN) to enable subscribers to make and receive calls from the landline public network. The cells A-E are shown as about the same size and may be the size of a "micro cell", i.e., about 500 meters in width. Such cells may require a maximum mobile station transmission power level of 200 mw. In this embodiment, system 1 provides variable rate transmission over the data links, with the forward and the reverse links, 20, 18, being either symmetric (same data rates) or asymmetric (different data rates).

#Referring now to FIG. 2A, the schematic block diagram therein shows portions of a transmitter modulator 100 for transmitting variable rate data on a reverse link of a cellular system according to an embodiment of the invention. Transmitter modulator 100, which may be utilized in the reverse link 18 of mobile station 14 of FIG. 1, includes an input circuit referred to for convenience as demultiplexer (DEMUX) 102, along with parallel convolutional coder/interleavers (CC/INT) 104, 106, 108, and 110, parallel Walsh modulators (Walsh mod.) 112, 114, 116, and 118, data burst randomizers 120, 122, 124, and 126, multiplexer (MUX) 128, transmission rate controller 130, long code generator 132, long code spreader 138, Q PN spreader 136, and I PN spreader 134.