Method and arrangement in a radio communication network

A method for controlling scanning of radio channels in a radio communication system, the controlling being performed by a mobile station in standby mode monitoring a control channel on which a first base station in a first radio communication network in the system transmits messages with control information, said method comprising the steps of:

• (a) receiving one of said messages in the mobile station, said message comprising at least one block of information bits, the block including a plurality of data bits and a plurality of check bits whose value depends on said data bits;
• (b) generating a first indication when said data bits are considered as correctly received;
• (c) determining upon generation of said first indication, a time period according to a predetermined rule during which the blocks of information bits conveying said message contain no new information intended for the mobile station;
• (d) determining whether the mobile station is mounted to a vehicle;
• (e) determining an amount of time elapsed since a previous channel scanning operation;
• (f) turning off portions of the mobile station during at least part of said time period if said elapsed amount of time is less than a predetermined amount of time and the mobile station is not vehicle mounted;
• and
• (g) scanning of said radio channels during at least part of said time period if said mobile station is vehicle mounted or said elapsed amount of time is greater than said predetermined amount of time.

A mobile station for operation in a radio communication system having at least a first radio communication network, said network having at least a first base station which transmits messages with control information on a control channel, the mobile station comprising:

• a receiver for receiving one of said messages in the mobile station, said message comprising at least one block of information bits, the block including a number of data bits and a number of check bits whose value depends on said data bits;
• a CRC check circuit for generating a first indication when said data bits are considered as correctly received;
• a time period calculator for determining, upon generation of said first indication, a time period according to a predetermined rule during which the blocks of information bits conveying said message contain no new information intended for the mobile station;
• and
• a scanning means for scanning of radio channels during at least part of said time period.

A mobile station for operation in a radio communication system comprising at least a first radio communication network, said network comprising at least a first base station which transmits messages with control information on a control channel, the mobile station comprising:

• a receiver for receiving one of said messages in the mobile station, said message comprising at least one block of information bits;
• the block including a number of data bits and a number of check bits whose value depends on said data bits;
• a CRC check circuit for generating a first indication when said data bits are considered as correctly received;
• a time period calculator for determining, upon generation of said first indication, a time period according to a predetermined rule during which the blocks of information bits conveying said message contain no new information intended for the mobile station;
• a scanning means for scanning of radio channels;
• a controller for determining whether the mobile station is mounted to a vehicle, the controller further for determining an amount of time elapsed since a previous channel scanning operation, the controller still further for entering a sleep mode for said time period if said elapsed amount of time is less than a predetermined amount of time and the mobile station is not vehicle mounted and initiating scanning if the mobile station is vehicle mounted or said elapsed amount of time is greater than said predetermined amount of time, and wherein said scanning means scanning for said radio channels during at least part of said time period.