Local radio communication system

• US 20040116114A1
• Filed: 01/30/2004
• Published: 06/17/2004
• Est. Priority Date: 02/28/2001
• Status: Active Grant

• Current Assignee: Inventel Systems
• Original Assignee: Inventel Systems
• Inventors: Carreel, Eric, Lewiner, Jacques
• Granted Patent: US 7,110,759 B2
• Time in Patent Office: Days
• US Class Current: 455/426.2
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 72/54 based on quality criteria

Abstract

The invention relates to a local radio communication system comprising a central controller (9), several bases (7) which are connected to the controller and several terminals (5) which communicate with the bases. The bases (7) communicate with the terminals using a local radio communication protocol with time division multiple access. Said bases are adapted to real-time transmit chronological information to the controller releasing to the transmissions planned for said bases. The controller is adapted to determine if there is a risk of interferences occurring between the planned transmissions and to impose a chronology for said planned transmissions on the bases in order to limit said interferences.

Claims

1. A local radiocommunication system comprising:

at least one central controller (9),

several bases (7) connected to the controller (9) and controlled by said controller,

and several terminals (5), each communicating with at least one of the bases (7) according to a master/slave process where the base (7) plays a role of master and the terminal plays a role of slave at least after setting up a radio link between said base (7) and said terminal (5),

the bases (7) communicating with the terminals (5) according to the same time division multiple access local radiocommunication protocol, said protocol providing, for each base, successive time slots (Si) during which either an uplink information packet (PI) sent by a terminal (5) to said base (7) or a downlink information packet (PI) sent by said base (7) to said terminal (5) are transmitted, and said base being adapted to determine in advance and impose planned transmissions between said base and said terminal, said planned transmissions comprising planned transmissions of downlink information and planned slots of uplink information, where the terminal is authorized to transmit an uplink information packet (PI) to the base, and at least some of said bases (7) being susceptible to reciprocal interference, preventing the reception by one of said bases of an uplink information packet (PI) when another of said bases is transmitting a downlink information packet (PI),

characterized in that the different bases (7) are adapted to transmit to the controller (9), in real time, at least chronological information relating to transmissions planned by said bases,

and in that said controller (9) is adapted to determine whether there is a risk of interferences occurring between said planned transmissions, and to impose on the bases (7) a chronology of said planned transmissions which enables at least some of said interferences to be avoided.

2. The local radiocommunication system as claimed in claim 1, in which the controller (9) is adapted to synchronize the different bases (7) among themselves, in such a way that all said bases transmit more or less during the same time slots (Si) and receive more or less during the same time slots (Si+1).

3. The local radiocommunication system as claimed in claim 2, in which the radiocommunication protocol provides transmissions of standard-length information packets (PI) extending at most over one time slot (Si), and transmissions of information packets of a longer duration extending over an odd number of more than 1 successive time slots, the controller (9) being adapted to impose on the different bases that all the standard-length uplink information packets (PI) corresponding to all said bases are transmitted during the same time slots alternately with other time slots in which all the standard-length downlink information packets (PI) corresponding to all said bases are transmitted.

4. The local radiocommunication system as claimed in claim 3, in which the radiocommunication protocol provides that the terminals send uplink information packets to the bases solely in response to a downlink information packet received from a base, and the controller is adapted:

when a base has to send a long information packet to a terminal, to prevent the other bases from sending to the other terminals a downlink information packet requesting a response for the duration of the transmission of said long information packet,

and, when a terminal has to send a long information packet to a base, to prevent the other bases from sending a downlink information packet for the duration of the transmission of this long information packet.

5. The local radiocommunication system as claimed in any one of the preceding claims, in which the controller has in its memory information indicating pairs of bases (7) susceptible to reciprocal interference, and is adapted to delay at least some of the planned transmissions only between said bases susceptible to reciprocal interference, so as to avoid at least some interferences.

6. The local radiocommunication system as claimed in claim 5, in which the bases (7) are adapted to each carry out measurements of the signals respectively received when the other bases (7) are transmitting a radio signal, the controller (9) being adapted to determine said pairs of bases susceptible to reciprocal interference on the basis of said measurements.

7. The local radiocommunication system as claimed in claim 5 or claim 6, in which:

the bases (7) are adapted to transmit to the controller, in addition to the chronological information, planned frequency information indicating the frequency at which the planned transmissions must take place,

the controller (9) has in its memory, for each pair of bases (7) susceptible to reciprocal interference, information indicating pairs of interference frequencies at which said bases are susceptible to reciprocal interference,

and said controller (9) is adapted to delay at least some of the planned transmissions only for said planned frequencies corresponding to a pair of interference frequencies between said bases susceptible to reciprocal interference, so as to avoid at least some interferences.

8. The local radiocommunication system as claimed in any one of the preceding claims, in which the bases (7) are adapted to transmit to the controller, in addition to the chronological information, planned transmission category information indicating at least whether the information to be transmitted is or is not voice, and the controller (9) is adapted not to delay a planned voice transmission.

9. The local radiocommunication system as claimed in any one of the preceding claims, in which the different bases (7) are disposed in the immediate vicinity of one another.

10. The local radiocommunication system as claimed in any one of the preceding claims, in which the controller (9) and the bases (7) are contained in the same unit (4).

11. The local radiocommunication system as claimed in any one of the preceding claims, in which the controller also acts as a concentrator and makes the bases communicate with an external link.

12. The local radiocommunication system as claimed in any one of the preceding claims, in which the bases (7) and the terminals (5) are adapted to communicate according to the BLUETOOTH protocol.