Multiplex communications – Communication over free space – Having a plurality of contiguous regions served by...
Reexamination Certificate
1997-08-04
2001-09-25
Nguyen, Chau (Department: 2663)
Multiplex communications
Communication over free space
Having a plurality of contiguous regions served by...
Reexamination Certificate
active
06295286
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to indicating a multi-slot channel in a TDMA radio system, in which the radio channel normally consists of one timeslot in frames made up of several successive timeslots.
2. Description of the Prior Art
In TDMA radio systems, such as many current digital cellular mobile communication systems, the radio channel is normally assigned to one timeslot in frames transmitted at radio frequency, made up of several successive timeslots. Current TDMA mobile communication systems and their radio terminals have been devised so as to enable traffic channels and control channels of various types to be formed in them. For instance in a GSM system, channels of various types, such as a traffic channel and an associated control channel, may share the capacity of the same timeslot. Some systems already allow more than one channel to be allocated at the same time. The GSM system also allows simultaneous assignment of two “half rate” traffic channels. As new services have been developed, it has turned out that, in order to achieve higher transmission capacity on a radio channel, TDMA radio systems and their radio terminals should preferably be designed to allow multi-slot channels to be readily formed and used. The present invention is specifically concerned with accomplishing this potential improvement.
EP patent specification A2 399 611 discloses a solution relating to the improvement indicated above, describing a system for rapidly assigning several duplex speech channels to a radio terminal with a view to gain higher data speed in data message transmission from the radio terminal. The basic idea of the system described is that the terminal keeps record of the use and the quality of the duplex speech channels. and whenever necessary, any additional speech channels required are directly assigned for data message transmission on the basis of the data in this record. The radio terminal may also utilize data provided by the base station and the system control unit about the availability of the speech channels, and in this conjunction, the paging or speech forming message provided by the base station may include data about the number of duplex speech channels required and/or about the numerals of the suggested channels. However, this system basically does not allow for assignment of successive physical channels. The configuration of this specification is characterised by including special provisions for swiftly making several speech channels available for rapid data transmission. The specification mentions signalling only in passing, stating that guidance data about the number of channels required and suggestions for channels to be assigned can be signalled to the radio terminal, the general impression being that this is also extra signalling for additional data transmission, apart from normal operation. In contrast. the purpose of the present invention is specifically to provide for signalling in the assignment of a multi-slot channel without increasing or complicating the signalling compared to normal operation.
OBJECT OF THE INVENTION
The procedure of forming a channel between a radio terminal in a TDMA radio system and the base station serving it usually requires a large amount of signalling. In the GSM system, in which the preferred embodiment of the present invention is set out, this signalling involves transmitting a message or a message element describing the channel to the radio terminal. This message element, referred to as the Channel Description Information Element in GSM, defines the channel parameters, such as the channel type and the timeslot used. Thus, in the case mentioned above, two half-speed traffic channels (TCH/H) being simultaneously assigned in GSM, signalling comprises transmitting, to each channel, an information element describing the respective channel. When several timeslots are to be connected, signalling by assigning each timeslot separately as though it would be a separate channel naturally involves a great inconvenience. Thus, the purpose of the invention is to provide a method for indicating a multi-slot channel which does not increase the amount of signalling compared to the signalling required for describing a channel using one timeslot. The essence of the method of the invention is that the required number of successive timeslots in a frame are assigned to a multi-slot channel.
SUMMARY OF THE INVENTION
To achieve the above purpose of the inventive method for indicating a multi-slot channel in signalling received over a radio terminal in a TDMA structure, in which a radio channel usually consists of one timeslot in successive frames sent at radio frequency and made up of several successive timeslots, and in which. in order to allocate a radio channel, a message is signalled to the radio terminal, the message containing one element describing the said one timeslot and at least one second element describing the channel, the method is characterised in that, to assign a multi-slot channel, at least one or any element of the message describing the channel is replaced with a code. which identifies the channel as a multi-slot channel and sets the number of successive timeslots to be included in the multi-slot channel, the element indicating one timeslot in the message being used to indicate the first timeslot among the successive timeslots to be included in the multi-slot channel.
The invention is applicable for instance to a channel description information element relating to GSM channel assignment signalling, in which the element defining the channel type and the subchannel is replaced with a code, in which the first numbers identify the channel as a multi-slot channel, and the last numbers define the number of timeslots to be included. Thus, the timeslot number included in the same octet of the information element indicates the first timeslot of the multi-slot channel.
REFERENCES:
patent: 5239545 (1993-08-01), Buchholz
patent: 5257257 (1993-10-01), Chen et al.
patent: 5515379 (1996-05-01), Crisler et al.
patent: 5577024 (1996-11-01), Malkamaki et al.
patent: EP 0 399 611 (1990-11-01), None
patent: EP 0605 312 A1 (1994-07-01), None
patent: WO 94/08431 (1994-04-01), None
patent: WO 94/10767 (1994-05-01), None
patent: WO 95/12931 (1995-05-01), None
patent: WO 95/31878 (1995-11-01), None
Nguyen Chau
Nokia Mobile Phones Limited
Perman & Green LLP
Trinh D
LandOfFree
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