Radio communication system and radio communication method

• US 8,325,701 B2
• Filed: 08/29/2007
• Issued: 12/04/2012
• Est. Priority Date: 09/01/2006
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Yamauchi, Takahisa, Nagai, Yukimasa, Taira, Akinori
• Primary Examiner(s): CHAN, SAI MING
• Application Number:
  US12/439,586
• Publication Number:
  US 20100016023A1
• Time in Patent Office: 1,924 Days
• Field of Search: 370/434, 370/343, 455/562.1
• US Class Current: 370/343
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/061 using feedback from receiving side
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04B 7/0802 using antenna selection H04B7/0868 takes precedence; antenna beam directivity switching H01Q3/24
• CPC Class Codes: H04B 7/088 using beam selection
• CPC Class Codes: H04L 27/0006 Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio for spectrum sharing between different networks H04W16/14
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0078 Timing of allocation
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

A base station of a radio communication system emits a radio wave having the same frequency by time division toward a plurality of specific areas from a plurality of antenna elements by using a multiple-beam antenna to form a plurality of spot beams, and transmits broadcast information through a plurality of beacon channels. Upon reception of the broadcast information, a terminal that exists in any one of the plurality of specific areas selects an optimum beacon channel, and transmits a communication establishment request and a bandwidth request to the base station through a request channel corresponding to information for identifying the antenna element, which is included in the broadcast information received through the selected optimum beacon channel. Upon reception of the requests, the base station schedules, when a channel is to be allocated, a channel allocation time including downlink and uplink data bandwidths and the like.

Claims

1. A radio communication system that conducts a communication between a base station and a plurality of terminals wirelessly,

wherein the base station comprises a multiple-beam antenna made up of a plurality of antennas, and emits radio waves having a same frequency at a same timing from the multiple-beam antenna toward a plurality of specific areas corresponding to the plurality of antennas without overlapping by time division to form a plurality of spot beams,

wherein radio frames transmitted between the base station and the terminals each comprise a plurality of beacon channels which are channels from the base station to all of the terminals and are allocated for each of the antennas, a plurality of request channels which are channels from all of the terminals to the base station and are allocated for each of the antennas, and a downlink channel and an uplink channel allocated to a request terminal, the plurality of request channels being arranged within each radio frame between the plurality of beacon channels and the downlink channel, each of the plurality of beacon channels and request channels within each of the radio frames has the same frequency,

wherein the base station transmits broadcast information including information for identifying the antenna from each of the plurality of antennas through the plurality of beacon channels, wherein when a terminal that exists in any one of the plurality of specific areas receives the broadcast information through the beacon channel, the terminal selects an optimum beacon channel from the plurality of beacon channels, and transmits a communication establishment request including information for identifying the antenna and a bandwidth request including a desired communication bandwidth to the base station through a single request channel which, among the plurality of request channels, corresponds to the information for identifying the antenna, which is included in the broadcast information received through the selected optimum beacon channel, and

wherein when the base station receives the communication establishment request and the bandwidth request through the request channel, the base station determines whether or not a channel is to be allocated to the frame for the request terminal, and when the channel is allocated, the base station schedules a modulation scheme and an encoding scheme for communicating with the request terminal, and a channel allocation time including the downlink data channel and the uplink data channel.

2. A radio communication system according to claim 1, wherein the multiple-beam antenna is made up of a plurality of sectors, and each of the sectors is made up of a plurality of antennas, and emits a radio wave different in frequency from an adjacent sector, and emits a radio wave identical in frequency to a spaced-apart sector.

3. A radio communication system according to claim 1, wherein the base station determines a connection time for each of the antennas, and controls a channel allocation time for communicating with the request terminal based on a traffic quantity grasped through the communication establishment request and the bandwidth request from the terminal, which are received from the plurality of antennas through the request channels.

4. A radio communication system according to claim 1, wherein the base station notifies the request terminal of presence/absence of a frame control header and a position of the frame control header within the frame through the beacon channel, and notifies the request terminal of the channel allocation time through the frame control header included in the downlink data channel.

5. A radio communication system according to claim 1, wherein the base station notifies the request terminal of the channel allocation time through the beacon channel.

6. A radio communication system according to claim 2, wherein the base station controls a construction of the frames of the sectors using the same frequency so that the downlink data channel and the uplink data channel, the downlink data channels, or the uplink data channels do not interfere with each other between the sectors using the same frequency.

7. A radio communication method of conducting a communication between a base station and a plurality of terminals wirelessly, the base station comprising a multiple-beam antenna made up of a plurality of antennas, and emits radio waves having a same frequency at a same timing from the multiple-beam antenna toward a plurality of specific areas corresponding to the plurality of antennas without overlapping in time division to form a plurality of spot beams, radio frames transmitted between the base station and the terminals each comprising a plurality of beacon channels which are channels from the base station to all of the terminals and are allocated for each of the antennas, a plurality of request channels which are channels from all of the terminals to the base station and are allocated for each of the antennas, and a downlink channel and an uplink channel allocated to a request terminal, the plurality of request channels being arranged within each radio frame between the plurality of beacon channels and the downlink channel, each of the plurality of beacon channels and request channels within each of the radio frames has the same frequency, the radio communication method comprising the steps of:

transmitting broadcast information including information for identifying the antenna from each of the plurality of antennas through the plurality of beacon channels;

upon reception of the broadcast information through the beacon channel, selecting an optimum beacon channel from the plurality of beacon channels, and transmitting a communication establishment request including information for identifying the antenna and a bandwidth request including a desired communication bandwidth from a terminal that exists in any one of the plurality of specific areas to the base station through a single request channel which, among the plurality of request channels, corresponds to the information for identifying the antenna, which is included in the broadcast information received through the selected optimum beacon channel; and

upon reception of the communication establishment request and the bandwidth request through the request channel, determining whether or not a channel is to be allocated to the frame for the request terminal, and when the channel is allocated, scheduling a modulation scheme and an encoding scheme for communicating with the request terminal, and a channel allocation time including the downlink data channel and the uplink data channel.

8. A radio communication method according to claim 7, wherein the multiple-beam antenna is made up of a plurality of sectors, and each of the sectors is made up of a plurality of antennas, and emits a radio wave different in frequency from an adjacent sector, and emits a radio wave identical in frequency to a spaced-apart sector.

9. A radio communication method according to claim 7, wherein the base station determines a connection time for each of the antennas, and controls a channel allocation time for communicating with the request terminal based on a traffic quantity grasped through the communication establishment request and the bandwidth request from the terminal, which are received from the plurality of antennas through the request channels.

10. A radio communication method according to claim 7, wherein the base station notifies the request terminal of presence/absence of a frame control header and a position of the frame control header within the frame through the beacon channel, and notifies the request terminal of the channel allocation time through the frame control header included in the downlink data channel.

11. A radio communication method according to claim 7, wherein the base station notifies the request terminal of the channel allocation time through the beacon channel.

12. A radio communication method according to claim 8, wherein the base station controls a construction of the frames of the sectors using the same frequency so that the downlink data channel and the uplink data channel, the downlink data channels, or the uplink data channels do not interfere with each other between the sectors using the same frequency.