Method of performing code synchronization, and receiver
AssigneeNokia Corporation
InventorsMarcos Katz, Savo Glisic, Jari Iinatti
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Abstract
The invention relates to a method of performing code acquisition on a signal to be received and to a receiver implementing the method. In the method the receiver receives a signal from a transmitter by at least two antenna beams, and to perform code acquisition, the antenna beams formed are searched at different delays of the spreading code. The number M of antenna beams can also be changed adaptively by determining a signal-to-noise ratio and by forming a number of antenna beams which is proportional to the signal-to-noise ratio. The receiver performs code acquisition by receiving a signal from the transmitter and by searching the antenna beams formed at the different delays of the spreading code.
Claims19
A method of performing code acquisition on a signal to be received, which is spread-coded with a pseudorandom spreading code, the method comprising:
- forming a signal-to-noise ratio estimate from the ratio of the level of the signal to be received to the level of interferences,
- forming a number of angular cells which is proportional to the signal-to-noise ratio estimate, and receiving a signal;
- and
- performing code acquisition by searching the angular cells formed at different delays of the spreading code,
- wherein the lower the level of the signal to be received in relation to the level of interferences, the more angular cells will be formed.
A method of performing code acquisition on a signal to be received, which is spread-coded with a pseudorandom spreading code, the method comprising:
- forming a signal-to-noise ratio estimate from the ratio of the level of the signal to be received to the level of interferences,
- forming a number of angular cells which is proportional to the signal-to-noise ratio estimate, and receiving a signal;
- performing code acquisition by searching the angular cells formed at different delays of the spreading code;
- and
- selecting the number of angular cells so that the code acquisition time is minimized.
A method of performing code acquisition on a signal to be received, which is spread-coded with a pseudorandom spreading code, the method comprising
- forming a signal-to-noise ratio estimate from the ratio of the level of the signal to be received to the level of interferences,
- forming a number of angular cells which is proportional to the signal-to-noise ratio estimate, and receiving a signal;
- performing code acquisition by searching the angular cells formed at different delays of the spreading code;
- and
- assuming, in order to form the signal-to-noise ratio estimate, that the signal to be received has a desired level and forming the number of angular cells needed in reception, the number being inversely proportional to the level of interferences.
A method of performing code acquisition on a signal to be received, which is spread-coded with a pseudorandom spreading code, the method comprising
- forming a signal-to-noise ratio estimate from the ratio of the level of the signal to be received to the level of interferences,
- forming a number of angular cells which is proportional to the signal-to-noise ratio estimate, and receiving a signal;
- performing code acquisition by searching the angular cells formed at different delays of the spreading code;
- and
- performing code acquisition in a base station of a radio system and estimating the level of interferences by means of the number of users served by the base station.
A receiver which is arranged to perform code acquisition on a signal to be received, which is spread-coded with a pseudorandom spreading code, the receiver comprising signal-to-noise ratio estimation means for determining a signal-to-noise ratio estimate from the ratio of the level of the signal to be received to the level of interferences, wherein the receiver being arranged to
- form a number of angular cells which is proportional to the signal-to-noise ratio and receive a signal;
- and
- perform code acquisition by searching the angular cells formed at different delays of the spreading code,
- wherein the smaller the level of the signal to be received in relation to the level of interferences, the more angular cells the receiver is arranged to form.
A receiver which is arranged to perform code acquisition on a signal to be received, which is spread-coded with a pseudorandom spreading code, the receiver comprising signal-to-noise ratio estimation means for determining a signal-to-noise ratio estimate from the ratio of the level of the signal to be received to the level of interferences, wherein the receiver being arranged to
- form a number of angular cells which is proportional to the signal-to-noise ratio and receive a signal;
- and
- perform code acquisition by searching the angular cells formed at different delays of the spreading code,
- wherein the receiver is arranged to select the number of angular cells so that the code acquisition time is minimized.
A receiver which is arranged to perform code acquisition on a signal to be received, which is spread-coded with a pseudorandom spreading code, the receiver comprising signal-to-noise ratio estimation means for determining a signal-to-noise ratio estimate from the ratio of the level of the signal to be received to the level of interferences, wherein the receiver being arranged to
- form a number of angular cells which is proportional to the signal-to-noise ratio and receive a signal;
- and
- perform code acquisition by searching the angular cells formed at different delays of the spreading code,
- wherein to form the signal-to-noise ratio estimate, the receiver is arranged to set the level of the signal to be received to a constant value and form the number of angular cells needed inversely proportionally with respect to the level of interferences.
A receiver which is arranged to perform code acquisition on a signal to be received, which is spread-coded with a pseudorandom spreading code, the receiver comprising signal-to-noise ratio estimation means for determining a signal-to-noise ratio estimate from the ratio of the level of the signal to be received to the level of interferences, wherein the receiver being arranged to
- form a number of angular cells which is proportional to the signal-to-noise ratio and receive a signal;
- and
- perform code acquisition by searching the angular cells formed at different delays of the spreading code,
- wherein the receiver is a base station of a radio system and the level of interferences is estimated by means of the number of users served by the base station.
Dependencies are inferred from the claim text.