Multiplex communications – Communication over free space – Combining or distributing information via time channels
Reexamination Certificate
1998-12-03
2002-05-28
Vincent, David (Department: 2661)
Multiplex communications
Communication over free space
Combining or distributing information via time channels
C370S466000
Reexamination Certificate
active
06396827
ABSTRACT:
The present invention relates generally to a manner by which to synchronize a mobile station in a radio communication system. More particularly, the present invention relates to apparatus, and an associated method, by which a synchronization signal generated by apparatus operable pursuant to a first cellular communication standard can be used to synchronize a mobile station operable pursuant to a second cellular communication standard. An embodiment of the present invention is advantageously utilized in the implementation of a so-called 3G (third generation) cellular communication system. The infrastructure of an existing IS-136 cellular communication system can be utilized to synchronize a mobile station which is operable pursuant to a time frame format defined in a GSM cellular communication system.
BACKGROUND OF THE INVENTION
In recent years, the utilization of wireless communication systems through which to communicate telephonically has achieved wide popularity. Conventional, voice communications as well as data communications can be effectuated telephonically through the use of such wireless communication systems.
In a wireless communication system, the communication channel formed between a sending and a receiving station is a radio channel, formed of a portion of the electromagnetic spectrum. A wire line connection is not required to effectuate the communication of a communication signal between the sending and receiving stations. Thereby, communication by way of a wireless communication system is possible at a location to which formation of a wire line connection would be impractical or impossible.
Cellular communication systems have been implemented using various communication schemes. Cellular communication systems have been developed which utilize, for example, FDMA (frequency-division, multiple-access), TDMA (time-division, multiple-access), CDMA (code-division, multiple-access) techniques, and various combinations of such techniques.
A cellular communication system includes network infrastructure which includes a plurality of spaced-apart base stations, formed of fixed-site radio transceivers. A user communicates with the infrastructure of a cellular communication network through the use of a radio telephone, typically referred to as a mobile station. The mobile station receives downlink signals on a forward link and transmits uplink signals on a reverse link. Thereby, two-way communications are provided between the infrastructure of the cellular communication network and the mobile station.
With continued improvements in communication technologies and the development of improved circuitry by which to implement such technologies, improvements to cellular communication systems have been proposed. Some proposals pertain to a so-called 3G (third generation) cellular communication standard. Such proposals for the 3G standard are intended to provide a cellular standard permitting universal implementation of a cellular system which shall be able to take advantage of the improved communication technologies to provide a system permitting increased capacity levels of communications and which provide increased communication services.
One such proposal is the UWC-136 HS (Universal Wireless Communications Consortium-136 High Speed) system. In this proposal, certain ones of the technologies and standards promulgated in two existing cellular communication systems are integrated together. Namely, the proposed, UWC-136 HS system integrates together components, and operation, of the existing IS-136/136+ communication system and the GSM/GPRS/EDGE (global system for mobile communications/general packet radio service/enhanced data rates for GSM evolution) system.
A problem associated with such integration is due to dissimilarities of the time frame structures defined in the systems. That is to say, the time frame structure of the IS-136/136+ system and the GSM system are dissimilar. Although both systems are TDMA (time-division, multiple-access) systems, the frames defined in the respective systems are of dissimilar lengths. A frame is a group of time slots. Channels defined in a TDMA system are defined, in part, in terms of the time slots during which signal bursts are transmitted. Both of the systems also define superframes to be groups of frames, and hyperframes to be groups of superframes. But, the superframe lengths and hyperframe lengths are defined to be of dissimilar lengths in their respective systems.
IS-136 and GSM standards define different signals to be used by the mobile in synchronization to the system. In GSM the common control channels are used for synchronization. These channels are SCH (synchronization channel), FCCH (frequency correction channel) and (P)BCCH ((Packet) Broadcast Control Channel). These common control channels are sent in a GSM cell on downlink Carrier CO on its time slot
0
. To enable synchronization and measurements by the mobile this carrier needs to be sent constantly at constant power by the base station.
And, the signal bandwidths of signals generated in the different systems are of differing bandwidths. In the IS-136 standard, channels are defined to be of 30 kilohertz bandwidths. And, in the GSM standards, channel bandwidths are of 200 kilohertz bandwidths.
When integrating the standards together to form the UWC-136 HS system, it would be beneficial if the IS-136 DCCH signal could be utilized in synchronization of the mobile to the 200 kHz GSM/GPRS/EDGE carrier. Synchronization of the mobile station from IS-136 DCCH to the 200 kHz carrier could be done quicker than by using the GSM synchronization signals. Also, existing plans for the implementation of the UWC-136 HS system allocates only a limited portion of the electromagnetic spectrum within which to define radio channels. Implementation proposals for the United States, for instance, provide only one megahertz of spectrum, thus necessitating a high level of channel reuse, such as on a 1/3 cell reuse pattern. The common control channels set forth in the existing GSM standard when broadcast in a system utilizing a 1/3 cell reuse pattern might result in excessive levels of interference. A 3G system necessitating a reduced level of signaling, relative to that utilized in a conventional GSM system, would be advantageous.
A manner by which to permit synchronization of a mobile station with the synchronization signals defined in the IS-136 system would advantageously permit synchronization to be performed more quickly and also obviate the need for certain of the synchronization signals utilized in a GSM communication system. The common control channels require bandwidth on the GSM carrier. In a low capacity initial deployment of 136HS it would be beneficial if this bandwidth could be used for packet data transfer. This capacity increase may be possible by using information present on the 30 kHz DCCH in synchronization to the GSM/GPRS/EDGE channel.
The UWC-136HS system will have both the EDGE coverage and 136 coverage in the area of the same cell. This means that the IS-136/136+ and GSM/EDGE base station transceivers will be located in the same cell site. From this perspective it does not seem reasonable that a mobile would need to use time to synchronize to a 200 kHz carrier on a cell where it already has synchronized to the 30 kHz carrier. A faster way would be to utilize information on the 30 kHz channel to make synchronization to the 200 kHz carrier faster.
It is in light of this background material related to synchronization between a mobile station and network infrastructure of a cellular communication system that the significant improvements of the present invention have evolved.
SUMMARY OF THE INVENTION
The present invention, accordingly, advantageously provides apparatus, and an associated method, by which a synchronization signal generated by apparatus operable pursuant to a first cellular communication standard can be used to synchronize a mobile station operable pursuant to a second cellular communication standard.
In one implementation, synchronization signals are g
Paivike Heikki
Pirhonen Riku
Nokia Corporation
Shaw Steven
Vincent David
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