Apparatus and method for transmitting and receiving a signaling message in a communication system

A mobile radio telephone, comprising:

• (a) means for synchronizing said mobile radio telephone to a paging channel of a communication system having varying levels of margin;
• (b) means for monitoring messages on said paging channel at the margin level in which said mobile radio telephone is synchronized thereto;
• (c) means for receiving messages through said paging channel at the synchronized margin level;
• and
• (d) means for providing a signal to alert a user of said mobile radio telephone when a signaling message is received through said paging channel at a synchronized margin level greater than a specified margin level.

A mobile satellite phone, comprising:

• (a) a main housing;
• (b) a signal processing circuit located inside said main housing for operating said mobile satellite phone in a satellite mode of communication, said signal processing circuit further comprising:
• (1) means for synchronizing said mobile satellite phone to a first paging channel and at least one alternative paging channel having a higher margin level than said first paging channel;
• (2) means for monitoring messages on said first paging channel and said alternative paging channel when synchronized with such respective paging channel;
• (3) means for receiving messages through said first paging channel and said alternative paging channel when monitoring such respective paging channel;
• and
• (4) means for providing a signal to alert a user of said mobile satellite phone when a signaling message is received through said alternative paging channel;
• and
• (c) an antenna coupled to said signal processing circuit for receiving signals from and transmitting signals to said paging channels.

In a communication system having a plurality of paging channels with varying margin levels, a method of alerting a user of a mobile radio telephone when a signaling message is received other than through a specified paging channel, said method comprising the steps of:

• (a) synchronizing said mobile radio telephone to one of said plurality of paging channels;
• (b) monitoring messages on the paging channel to which said mobile radio telephone is synchronized;
• (c) receiving messages on said synchronized paging channel;
• and
• (d) alerting said user of said mobile radio telephone when said signaling message is received through a paging channel other than said specified paging channel.

A control unit for a communication system including a plurality of mobile radio telephones, comprising:

• (a) first means for transmitting a signaling message at a first margin level to anintended mobile radio telephone via a first paging channel;
• (b) means for determining whether said intended mobile radio telephone is synchronized to said first paging channel;
• (c) second means for transmitting said signaling message at a margin level greater than said first margin level, said second transmitting means being automatically activated when synchronization of said intended mobile radio telephone to said first paging channel has not occurred within a predetermined number of transmission attempts by said first transmitting means;
• (d) means for exchanging messages with said intended mobile radio telephone upon synchronization of said intended mobile radio telephone to said first paging channel at said first margin level;
• (e) means for aborting the transmission of said signaling message by said control unit if synchronization by said mobile radio telephone is not acquired at said greater margin level within a predetermined number of transmission attempts by said second transmission means;
• and
• (f) means for retrying transmission of said signaling message by said first and second transmitting means after a predetermined time period.

A method of transmitting a signaling message between a control unit and a plurality of mobile radio telephones in a communication system, said method comprising the following steps:

• (a) transmitting said signaling message by said control unit via a first paging channel at a first margin level to one of said mobile radio telephones;
• (b) determining whether said mobile radio telephone is synchronized to said first paging channel;
• (c) transmitting said signaling message at a margin level greater than said first margin level when synchronization to said first paging channel by said mobile radio telephone has not occurred within a predetermined number of transmission attempts by said control unit at said first margin level;
• (d) exchanging messages between said control unit and said mobile radio telephone upon synchronization to said first paging channel by said mobile radio telephone;
• (e) aborting the transmission of said signaling message by said control unit if said acknowledgement signal is not received within a predetermined number of attempts during said second transmitting step;
• and
• (f) retrying said first and second transmitting steps after a predetermined time period.

A communication system, comprising:

• (a) a plurality of mobile radio telephones;
• (b) a control unit for transmitting a signaling message to an intended mobile radio telephone;
• and
• (c) at least one paging channel through which said control unit is able to transmit said signaling message at varying margin levels, wherein said control unit initially transmits said signaling message at a specified margin level for a predetermined number of attempts and automatically continues to transmit said signaling message at margin levels progressively greater than said specified margin level until said intended mobile radio telephone receives said signaling message;
• wherein each said mobile telephone further includes means for monitoring messages on a paging channel to which said mobile radio telephone is synchronized and means for providing a signal to alert a user of said mobile radio telephone when said signaling message is received through a paging channel having a margin level greater than said specified margin level.