Multiplex communications – Communication over free space – Having a plurality of contiguous regions served by...
Reexamination Certificate
1997-09-09
2001-05-22
Marcelo, Melvin (Department: 2663)
Multiplex communications
Communication over free space
Having a plurality of contiguous regions served by...
C370S342000
Reexamination Certificate
active
06236646
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to mobile communications systems and, in particular, to a system for scheduling uplink and downlink communications access for packet data communications.
2. Description of Related Art
The next generation of mobile communications systems (comprising, for example, wideband cellular systems) will be required to provide a broad selection of telecommunications services including digital voice, video significantly. This may result in much higher traffic density on the limited communications resources of the system.
In a spread spectrum (code division multiple access) type wideband cellular system, each mobile station has access to its own set of uplink code channels for use in supporting use of the available telecommunications services. These sets of uplink codes between mobile stations, however, due to synchronization concerns, are not experienced as being orthogonal to each other. Accordingly, interference to a limited degree occurs between mobile stations when plural mobile stations simultaneously engage in call communications. In spite of efforts to dynamically control transmit power levels, and thus control interference, this experienced interference may rise to an unacceptable level as an increasingly large number of mobile station calls are processed.
The foregoing interference problem is of special concern in connection with the provision of packet data telecommunications services on the uplink. This is because the traffic being handled by the communications system tends to be very bursty in nature and it is very difficult to predict service access. If a significant number of these uplink bursts occur simultaneously, interference between mobile stations may rise to a sufficient level to impair or block successful communications transmission, not only for the data telecommunications service, but possibly for other telecommunications services as well. There is a need then for a system and method for scheduling mobile station access to the uplink for the purpose of making a packet data communications transmission.
Furthermore, similar concerns exist with respect to interference caused by bursty downlink packet data communications transmissions to mobile station. Thus, there is also a need for a system and method for scheduling base station access to the downlink for the purpose of making a packet data communications transmission.
SUMMARY OF THE INVENTION
Responsive to a mobile station request to make an uplink data packet transmission, a telecommunications system grants the mobile station transmission access. A schedule for authorized mobile station access to make an uplink data packet transmission in a next frame is then determined by the system, with that schedule transmitted from the base station to plural mobile stations, including the requesting mobile station, in a current frame. Each mobile station scheduled with authorization to make an access in the next frame then transmits its data packet (or a portion thereof) to the base station during that next frame. The system, in selectively organizing the access schedule for mobile station data packet transmissions on a per frame basis, effectively exercises control over when mobile stations may make uplink communications and thus controls the level of interference generated by multiple mobile station transmissions.
With respect to the downlink, the telecommunications system determines a schedule for the transmission of data packets by a base station to served mobile stations. In accordance with this schedule, the base station transmits a notification in a current frame to a destination mobile station that a data packet is about to be delivered in a next frame. Responsive thereto, the mobile station access the appropriate code channel and receives the message in the next frame.
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European Patent Office, Standard Search Report RS100211, Mar. 4, 1998.
Beming Per
Johansson Mathias
Lundsjö Johan
Roobol Christiaan
Jenkens & Gilchrist
Marcelo Melvin
Telefonaktiebolaget LM Ericsson (publ)
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