Method and arrangement for reducing power consumption in user equipments in multi-carrier radio systems
View Patent ↗The present invention relates to a method and an arrangement for reducing power consumption in the user equipments in power saving mode in a communication network, comprising a communication network node transmitting information on shared control channels (SCCH) to one or more user equipments. The information is transmitted over either a narrow or a wide bandwidth depending on which mode said one or more user equipments are, either a power saving mode or an active mode.
1. A method for efficiently utilizing radio resources in a communication network comprising a communication network node transmitting information on control channels to one or more user equipments, comprising:
defining a subset of Transmission Time Intervals in order to determine at which instances a control channel may address a user equipment in a power saving mode or non-power saving mode;
defining a first, wideband mapping pattern for user equipments in a non-power saving mode;
defining a second, narrowband mapping pattern for user equipments in a power saving mode;
transmitting, during Transmission Time Intervals of a subset associated to a respective power mode, said information over the control channel by using the mapping pattern that is defined for the respective power mode of the user equipment; and
wherein information is allowed to be transmitted over the control channel to user equipments in non-power saving modes by using the second mapping pattern if no information is to be transmitted to user equipments in a power saving mode.
2. The method according to claim 1 , wherein said second mapping pattern is used for signalling of indications pointing to a certain message.
3. The method according to claim 1 , wherein said second mapping pattern is used for at least one of paging and broadcast messages.
4. The method according to claim 1 , wherein using said second mapping pattern implies mapping on a pseudo-random set of subcarriers.
5. The method according to claim 1 , whereby using said first mapping pattern implies a mapping on a subset of non-contiguous subcarriers covering a major part of a system bandwidth.
6. The method according to claim 1 , wherein using said second mapping pattern implies a mapping on a subset of contiguous subcarriers.
7. The method according to claim 1 , wherein said control channel is interleaved on a wide or narrow bandwidth depending on the power mode of the user equipment.
8. The method according to claim 1 , wherein the communication network applies Orthogonal Frequency Division Multiplexing (OFDM).
9. An apparatus for efficiently utilizing radio resources in a communication network, said apparatus included in or associated to a communication network node for transmitting information on control channels to one or more user equipments, comprising:
a first unit for providing subsets of Transmission Time Intervals in order to determine at which instances a control channel may address a user equipment in a power saving mode or non-power saving mode;
a second unit for providing a first, wideband mapping pattern for user equipments in a non-power saving mode and a second, narrowband mapping pattern for user equipments in a power saving mode;
a transmitter adapted to transmit, during Transmission Time Intervals of pre-defined subsets associated to a respective power mode, said information over the control channel by using the mapping pattern that is defined for the respective power mode of the user equipment; and
wherein information is allowed to be transmitted over the control channel to user equipments in non-power saving modes by using the second mapping pattern if no information is to be transmitted to user equipments in a power saving mode.
10. The apparatus according to claim 9 , wherein the communication network applies Orthogonal Frequency Division Multiplexing (OFDM).