Method and an apparatus for re-establishing wireless communication between a base unit and a remote unit

A wireless communication system for communication between a base unit and a remote unit, said system comprising:

• means for transmitting by the base unit to the remote unit a table of channels of communication to be used between the base unit and the remote unit;
• means for receiving the table transmitted by the base unit, by the remote unit;
• means for storing the table received by the remote unit;
• means for generating a clock signal by the base unit;
• means for transmitting, by the base unit to the remote unit, the clock signal value;
• means for applying a function by the base unit to the value of the clock signal to obtain an entry in the table in the base unit, in the event of a break in the communication link between the base unit and the remote unit;
• means for selecting the channel of communication associated with the entry in the table by the base unit;
• means for receiving said clock signal value by said remote unit;
• means for generating an internal clock signal by the remote unit synchronized with said clock signal value;
• means for applying the same function by the remote unit to the value of the internal clock signal at the remote unit, to obtain an entry in the table in the event of a break in the communication link between the base unit and the remote unit;
• and
• means for selecting the channel of communication associated with the entry in the table by the remote unit,
• whereby communication is re-established over the channel of communication associated with the entry in the table.

A method of establishing a wireless communication link between a base unit and a remote unit comprising:

• selecting one of a plurality of frequency channels by said base unit;
• transmitting periodically a sync signal in a first selected time period in said one frequency channel selected by the base unit;
• scanning said plurality of frequency channels, one at a time, by said remote unit for the detection of said sync signal;
• transmitting a first response signal in said one frequency channel by said remote unit, in response to the detection of said sync signal, in a second selected time period, different from the first selected time period,
• transmitting a table of channels of communication signal and a clock signal value, encoded by a code by the base unit in said one frequency channel, in a third selected time period, different from the first and second selected time periods,
• receiving said table signal and clock signal value by the remote unit, in said third time period;
• decoding said table signal and clock signal value by the remote unit in said third time period to derive the table of channels of communication and synchronizing a clock signal generated internal to said remote unit with said received clock signal value;
• storing said table by the remote unit;
• communicating between said remote unit and said base unit;
• wherein in the event of a break in the communication link, re-establishing the communication link by:
• continuing counting clock signal by the remote unit from a clock signal generated internal thereto;
• applying a function by the remote unit to the value of the clock signal at the remote unit to obtain an entry in the table;
• selecting the channel of communication associated with the entry in the table by the remote unit;
• continuing counting clock signal by the base unit;
• applying the same function by the base unit to the value of the clock signal at the base unit to obtain an entry in the table;
• and
• selecting the channel of communication associated with the entry in the table by the base unit;
• whereby communication is re-established over the channel of communication associated with the entry in the table.

An apparatus for establishing a wireless communication link between a base unit and a remote unit comprising:

• means for selecting one of a plurality of frequency channels by said base unit;
• means for transmitting periodically a sync signal in a first selected time period in said one frequency channel selected by the base unit;
• means for scanning said plurality of frequency channels, one at a time, by said remote unit for the detection of said sync signal;
• means for transmitting a first response signal in said one frequency channel by said remote unit, in response to the detection of said sync signal, in a second selected time period, different from the first selected time period;
• means for transmitting a table of channels of communication signal and a clock signal value encoded by a code by the base unit in said one frequency channel, in a third selected time period, different from the first and second selected time periods;
• means for receiving said table signal, and clock signal value by the remote unit, in said third time period;
• means for decoding said table and clock signal value by the remote unit to derive the table of channels of communication and for synchronizing a clock signal generated internal to said remote unit with said received clock signal value;
• means for applying a function by the base unit to the value of the clock signal to obtain an entry in the table in the base unit, in the event of a break in the communication link between the base unit and the remote unit;
• means for selecting the channel of communication associated with the entry in the table by the base unit;
• means for generating an internal clock signal by the remote unit;
• means for applying the same function by the remote unit to the value of the internal clock signal at the remote unit, to obtain an entry in the table, in the event of a break in the communication link between the base unit and the remote unit;
• and
• means for selecting the channel of communication associated with the entry in the table by the remote unit;
• whereby communication is re-established over the channel of communication associated with the entry in the table.