Radio relay system

• US 6,728,541 B2
• Filed: 02/23/2001
• Issued: 04/27/2004
• Est. Priority Date: 02/29/2000
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takahashi, Masahiro, Ueda, Shinichi, Hamada, Takuji, Masuko, Hideaki, Ohkura, Yoshinori
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): Lee, John J
• Application Number:
  US09/790,666
• Publication Number:
  US 20010018328A1
• Time in Patent Office: 1,159 Days
• Field of Search: 455/445, 455/403, 455/15, 455/419, 455/16, 455/3.03, 455/3.04, 455/3.05, 370/403, 370/404, 370/405, 370/419, 370/258
• US Class Current: 455/445
• CPC Class Codes: H04B 7/15542 Selecting at relay station its transmit and receive resources selection of wireless resources by user or terminal H04W72/02; arrangements affording multiple use of the transmission path by two-dimensional division of the resources H04L5/0003, or by allocating sub-channels H04L5/003
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04L 12/42 Loop networks
• CPC Class Codes: H04W 16/26 Cell enhancers or enhancement, e.g. for tunnels, building shadow

Abstract

A plurality of radio relay stations 1 are connected so that bi-directional ring-like paths are made up of radio transmission paths. The respective radio relay stations 1 bidirectionally transmit data inputted from terminals placed thereunder onto the bidirectional ring-like paths respectively. The respective data are respectively received by radio relay stations 2 having data destination terminals placed thereunder along the bidirectional ring-like paths. Each radio relay station, which has received the data destined for the terminals placed thereunder from both directions, transmits earlier incoming data to each terminal placed thereunder and discards later incoming data.

Thus, a radio relay system can be implemented which is capable of relaying data with a high degree of reliability.

Claims

1. A radio relay system having a plurality of radio relay devices for performing the relay of communication data between communication devices by radio transmission, comprising:

a plurality of radio transmission paths for ring-connecting said plurality of radio relay devices;

said each radio relay device including,

a local interface for holding one or plural communication devices;

relay means for relaying communication data received from an immediately preceding radio transmission path on a ring, which is formed by the ring connection to an immediately following radio transmission path on the ring when the data is not destined for each communication device held by a corresponding radio relay device;

receiving means for transmitting the communication data received from the on-ring immediately preceding radio transmission path to the corresponding communication device held through the local interface when the communication data is destined for the communication device held by said corresponding radio relay device; and

transmitting means for transmitting communication data received from the communication device held through the local interface to the on-ring immediately following radio transmission path.

2. The radio relay system according to claim 1, wherein said plurality of radio transmission paths ring-connect said plurality of radio relay devices in double form so that the directions of data transmission are reversely turned relative to each other,

said each radio relay device transmits the communication data received from the communication device held through the local interface to immediately following radio transmission paths on two rings formed by the double ring connection through the use of said transmitting means, and

transmits only one communication data of the same communication data destined for the communication devices held by said corresponding radio relay device, said same communication data being received from the immediately preceding radio transmission paths on the two rings, to the communication device held through the local interface through the use of said receiving means.

3. The radio relay system according to claim 2, wherein said each radio relay device transmits only communication data received earlier on a time basis, of the same communication data destined for the communication devices held by said corresponding radio relay device, said same communication data being received from the immediately preceding radio transmission paths on the two rings, to the communication device held through the local interface through the use of said receiving means.

4. The radio relay system according to claim 1, 2 or 3, wherein said each radio relay device further includes determining means for determining a frequency-based resource or a time-based resource used in at least one of the on-ring immediately preceding radio transmission path and on-ring immediately following radio transmission path so as not to interfere with other radio transmission paths.

5. The radio relay system according to claim 1, wherein said plurality of radio transmission paths are capable of bidirectional communications,

said each radio relay device allows said transmitting means to transmit communication data received from the communication device held through the local interface to respective radio transmission paths with respect to on-ring immediately following radio relay devices on both sides through the use of bidirectionally-communicable rings formed by the ring connection, and

allows said receiving means to transmit only one of the same communication data destined for the communication devices held by said corresponding radio relay device, said same communication data being received from on-ring immediately preceding radio transmission paths present in respective directions on the rings, to the communication device held through the local interface.

7. The radio relay system according to claim 5, wherein said each radio relay device further includes determining means for determining a frequency-based resource or a time-based resource or coding of data or modulation of data used in at least one of the on-ring immediately preceding radio transmission path and the on-ring immediately following radio transmission path so as to differ from other radio transmission paths each other.

8. The radio relay system according to claim 1, further comprising:

failure avoiding means for connecting said plurality of radio devices in ring form through the use of bidirectionally-communicable plural radio transmission paths and transmitting and receiving the communication data between arbitrary two radio devices through the use of one of bidirectionally-communicable rings formed by the ring connection.

9. The radio relay system according to claim 3, wherein said each radio relay device adds serial numbers to communication data relayed onto the two rings, and the corresponding radio relay device having received the communication data therein determines, based on the serial numbers whether said each communication data corresponds to communication data received earlier on a time basis.

6. The radio relay system according to claim 6, wherein said each radio relay device transmits only communication data received earlier on a time basis, of the same communication data destined for the communication device held by said corresponding radio relay device, said same communication data being received from the on-ring immediately preceding radio transmission paths present in the respective directions on the rings, to the communication device held through the local interface through the use of said receiving means.

10. The radio relay system according to claim 6, wherein said each radio relay device adds serial numbers to communication data relayed onto the rings, and the corresponding radio relay device having received the communication data therein determines, based on the serial numbers whether the communication data corresponds to communication data received earlier on a time basis.

11. A method of avoiding a failure developed in a radio relay system having a plurality of radio relay devices for performing the relay of communication data between communication devices by radio transmission, including:

a plurality of radio transmission paths for ring-connecting said plurality of radio relay devices;

said each radio relay device including,

a local interface for holding one or plural communication devices;

relay means for relaying communication data received from an immediately preceding radio transmission path on a ring, which is formed by the ring connection to an immediately following radio transmission path on the ring when the data is not destined for each communication device held by a corresponding radio relay device;

receiving means for transmitting the communication data received from the on-ring immediately preceding radio transmission path to the corresponding communication device held through the local interface when the communication data is destined for the communication device held by said corresponding radio relay device; and

transmitting means for transmitting communication data received from the communication device held through the local interface to the on-ring immediately following, comprising the steps of;

ring-connecting said plurality of radio relay devices in double form through the use of a plurality of radio transmission paths so that the directions of data transmission are reversely turned relative to each other;

transmitting and receiving the communication data between arbitrary two radio relay devices through the use of one of two rings formed by the double ring connection; and

transmitting and receiving the communication data through the use of the other ring when a failure occurs in said one ring.