Radio communication system for reducing interferences with respect to other communication system using close frequency band

• US 6,961,577 B2
• Filed: 05/24/2002
• Issued: 11/01/2005
• Est. Priority Date: 05/25/2001
• Status: Expired due to Term

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Nagato, Rie, Uebayashi, Shinji, Ishiguro, Takayuki, Nakamura, Osamu
• Primary Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US10/153,899
• Publication Number:
  US 20020177444A1
• Time in Patent Office: 1,257 Days
• Field of Search: 455/450, 455/452.1, 455/436, 455/446, 455/447, 455/451, 455/440, 455/422, 455/509
• US Class Current: 455/450
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04M 15/8044 Least cost routing
• CPC Class Codes: H04M 2215/2026 Wireless network, e.g. GSM, PCS, TACS
• CPC Class Codes: H04M 2215/32 Involving wireless systems
• CPC Class Codes: H04M 2215/42 Least cost routing, i.e. provision for selecting the lowest cost tariff
• CPC Class Codes: H04M 2215/745 Least cost routing, e.g. Automatic or manual, call by call or by preselection
• CPC Class Codes: H04W 16/10 Dynamic resource partitioning
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 4/24 Accounting or billing
• CPC Class Codes: H04W 52/0238 where the received signal is an unwanted signal, e.g. interference or idle signal
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A communication channel allocation method allocates a communication channel to communications between a mobile terminal device and a second radio base station using a second frequency band which is close to a first frequency band used by a first radio base station, by detecting a first distance between the second radio base station and the first radio base station, detecting a second distance between the second radio base station and the mobile terminal device when the first distance is less than a first threshold, and allocating a communication channel of a frequency far from the first frequency band in the second frequency band to the communications between the second radio base station and the mobile terminal device when the second distance is less than a second threshold.

Claims

1. A communication channel allocation method for allocating a communication channel to communications between a mobile terminal device and a second radio base station using a second frequency band which is close to a first frequency band used by a first radio base station, the communication channel allocation method comprising the steps of:

controlling a received power of signal form the one mobile terminal device at the second radio base station to be constant;

obtaining allocation rates for channels to be used for communications between the second radio base station and the one mobile terminal device according to a total number of mobile terminal devices that are carrying out communications with the second radio base station and a total received power of signals other than signals from the one mobile terminal device;

obtaining a channel switching distance to be a criterion for switching communication channels, according to the allocation rates;

detecting a distance between the second radio base station and the one mobile terminal device; and

allocating a communication channel of a frequency far from the first frequency band in the second frequency band to the communications between the second radio base station and the mobile terminal device when the distance is greater than the channel switching distance.

2. The communication channel allocation method of claim 1, wherein the allocating step allocates a communication channel among a group of channels of frequencies far from the first frequency band in the second frequency band.

3. The communication channel allocation method of claim 1, wherein the allocating step allocates a communication channel of a frequency close to the first frequency band in the second frequency band to the communications between the second radio base station and the mobile terminal device when the distance is less than or equal to the channel switching distance.

4. The communication channel allocation method of claim 3, wherein the allocating step allocates available communication channel among a group of channels of frequencies close to the first frequency band in the second frequency band.

5. A communication control device for controlling a communication channel to be used for communications between one mobile terminal device and a second radio base station using a second frequency band which is close to a first frequency band used by a first radio base station, the communication control device comprising:

a received power control unit configured to control a received power of signals from the one mobile terminal device at the second radio base station to be constant;

an allocation rate calculation unit configured to obtain allocation rates for channels to be used for communications between the second radio base station and the one mobile terminal device according to a total number of mobile terminal devices that are carrying out communications with the second radio base station and a total received power of signals other than signals from the one mobile terminal device;

a distance calculation unit configured to obtain a channel switching distance to be a criterion for switching communication channels, according to the allocation rates;

a distance detection unit configured to detect a distance between the second radio base station and the one mobile terminal device; and

a channel allocation unit configured to allocate a communication channel of a frequency far from the first frequency band in the second frequency band to the communications between the second radio base station and the mobile terminal device when the distance is greater than the channel switching distance.

6. The communication control device of claim 5, wherein the channel allocation unit is configured to allocate available communication channel among a group of channels of frequencies far from the first frequency band in the second frequency band.

7. The communication control device of claim 5, wherein the channel allocation unit is also configured to allocate a communication channel of a frequency close to the first frequency band in the second frequency band to the communications between the second radio base station and the mobile terminal device when the distance is less than or equal to the channel switching distance.

8. The communication control device of claim 7, wherein the channel allocation unit is configured to allocate available communication channel among a group of channels of frequencies close to the first frequency band in the second frequency band.