Multiplex communications – Communication over free space – Having a plurality of contiguous regions served by...
Reexamination Certificate
1997-12-03
2001-01-30
Jung, Min (Department: 2739)
Multiplex communications
Communication over free space
Having a plurality of contiguous regions served by...
C370S335000, C370S445000
Reexamination Certificate
active
06181683
ABSTRACT:
TECHNICAL FIELD
The present invention concerns communication systems employing Code-Division Multiple Access (CDMA).
BACKGROUND OF THE INVENTION
Current digital cellular systems such as the Global System for Mobile Communication (GSM) or the Digital Cellular System 1800 (DCS-1800) in Europe, and the Personal Communication Networks (PCN) planned in the U.S. support mainly voice, message, and low-rate connection-oriented data services which are not well suited to support packet-based data communication.
Many mobile computer applications, however, require infrequent transfers of single or multiple data packets over the radio link of the mobile communication system. Some of them, e.g., e-mail, tele-shopping and tele-banking, and vehicle-dispatch or fleet management applications may be well served with a store-and-forward short message service. Others, among them terminal emulation, remote access to local area network (LAN) based servers, or credit-card verification require interactive usage, tolerate little delay, and are characterized by a wide distribution of packet length. There is little doubt that future mobile telecommunication systems such as the Universal Mobile Telecommunication System (UMTS) will have to support such data applications with an efficient packet-data service. In fact, the European Telecommunication Systems Institute (ETSI) is already in the process of defining such a service, called General Packet Radio Service (GPRS), as an extension to the current GSM system.
In the sequel, we will consider connection-less packet-data services for UMTS and PCN systems. In particular, we focus on the UMTS system which was developed in a code division testbed (CODIT) project under the umbrella of the Research in Advanced Communications in Europe (RACE) program. The CODIT system employs spread-spectrum transmission and code division multiple access (CDMA) and supports voice, message, and connection-oriented data services. For more details on the CODIT system please refer to “Design Study for a CDMA Based Third-Generation Mobile Radio System”, A. Baier et al., IEEE J. Selected Areas Commun., Vol. 12, 1994, pp. 733-743. CDMA systems are of particular interest because they promise higher capacity and more ease of deployment than competing time-division multiple access (TDMA) systems.
It is an object of the present invention to provide a method and apparatus which enables CDMA-based UMTS and PCN systems to support a connectionless packet-radio service.
It is a further object of the present invention to provide a communication system with added functionalities.
SUMMARY OF THE INVENTION
This has been achieved by the transmission of data packets over a code division multiple access wireless channel (PRCH), reserved for data packet services, from a transmitting station (MSy) to a receiving station (BS) of a code division multiple access communication system, comprising the following steps:
sending a request from said transmitting station (MSy) to the corresponding base station (BS) of said communication system indicating the destination address to which said data packet(s) are to be routed,
registering said transmitting station (MSy) and assigning a unique virtual connection identifier (VCIy) to it,
switching said transmitting station (MSy) to said channel (PRCH),
listening to the downlink of said channel (PRCH) until said base station (BS) broadcasts that it will be “idle”, i.e. that a random access to said channel (PRCH) is allowed in the next frame,
ramping up the transmission power of said transmitting station (MSy) during said next frame until a certain power level is reached,
transmitting said data packet(s) and said virtual connection identifier (VCIy) over the uplink of said channel (PRCH) to said base station (BS), and
rerouting said data packet(s) to said destination address, the access to said channel (PRCH) being controlled by a multiple access protocol based on carrier sensing and collision detection (CSMA/CD).
REFERENCES:
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patent: 5668880 (1997-09-01), Alajajian
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Chevillat Pierre R.
Cideciyan Roy D.
Rupf Marcel
Schott Wolfgang H.
Fitch Even Tabin & Flannery
Herzberg Louis P.
International Business Machines Corp.
Jung Min
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