Training sequence in digital cellular radio telephone system
AssigneeNokia Mobile Phones Ltd.
InventorsEsa Malkamaki, Pekka Ranta
Life of this patent
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Abstract
In radio phone systems with a digital cellular design currently used a training sequence of constant length, consisting of an guard part and a reference part, is included in a transmission burst between a base station and a mobile station. With the aid of a received training sequence, the receiver calculates the impulse response of the channel and is thereafter adapted into the channel. The quality of the connection can, according to the invention, be enhanced in that the training sequence is made adaptive, whereby the lengths of the guard part and the reference part may vary while the total length of the training sequence remains the same. According to another embodiment, also the total length of the training sequence is changed.
Claims20
A digital cellular system, comprising at least one base station for communication with subscriber equipment, and in which between a base station that includes a transmitter and a receiver and a subscriber equipment that also includes a transmitter and a receiver a radio channel can be established for the transmission of a transmission burst by at least one of said base station and said subscriber equipment, in which radio channel a training sequence having a recognizable symbol sequence is included in a transmission burst transmitted by said at least one of said base station and said subscriber equipment, said recognizable symbol sequence comprising a plurality of symbols for expressing a reference part and at least one additional part, whereby a receiver of at least one of said base station and said subscriber equipment can adapt itself to the radio channel according to an impulse response measured in the radio channel in accordance with the received training sequence, characterized in that the at least one of said reference part and said other part of said recognizable symbol sequence are not comprised, for all transmission bursts, of a constant number of said plurality of symbols.
A method for operating a digital cellular system of a type that includes a base station in bidirectional wireless communications with a user terminal through a communications channel, comprising the steps of:
- transmitting a burst of data by at least one of the base station and the user terminal between the base station and the user terminal, the burst including an information data portion and a training data portion, the training data portion being used to compensate a receiver of the burst for an impairment in the communications channel;
- wherein the training data portion includes at least a first sequence of bits and at least one second sequence of bits;
- and wherein
- the step of transmitting includes a step of adaptively varying at least one of a number of bits of the first bit sequence and a number of bits of the at least one second bit sequence in accordance with a degree of impairment of the communications channel.
A method for operating a digital cellular system of a type that includes a base station in bidirectional wireless communications with a user terminal through a communications channel, comprising the steps of:
- transmitting a burst of data by at least one of the base station and the user terminal between the base station and the user terminal, the burst including an information data portion and a training data portion, the training data portion being used to compensate a receiver of the burst for an impairment in the communications channel;
- wherein the training data portion includes at least a reference sequence of symbols and at least one guard sequence of symbols;
- and wherein
- the step of transmitting includes a step of adaptively varying at least one of a number of symbols of the reference symbol sequence and a number of symbols of the at least one guard symbol sequence in accordance with a degree of impairment of the communications channel.
Dependencies are inferred from the claim text.