RADIO SYSTEM, RADIO BASE STATION AND RADIO TERMINAL

• US 20130294373A1
• Filed: 06/28/2013
• Published: 11/07/2013
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: International Semiconductor Group
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Matsuo, Ryoko, Hirano, Tatsuma, Nabetani, Toshihisa, Adachi, Tomoko, Toshimitsu, Kiyoshi
• Granted Patent: US 9,167,600 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 74/0816 with collision avoidance
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

One of a plurality of radio terminals that transmit radio signals to a radio base station under a space multiplexing scheme, including a receiving unit that receives an access right request signal with respect to the radio base station from an other radio terminal, a prevention unit that prevents transmission of radio signals when receiving radio signals directed to an other radio terminal, a cancellation unit that cancels the prevention of transmission when receiving an access right assignment signal during the prevention of transmission and a transmitting unit that transmits a data signal to the radio base station according to the assignment signal, wherein radio signals are transmitted to the radio base station simultaneously with the other radio terminals and under the space multiplexing scheme.

Claims

1. One of a plurality of radio terminals, comprising:

a receiving unit configured to receive a request signal from another radio terminal of the plurality of radio terminals, the request signal comprises a request for an access right to transmit radio signals to a radio base station, the request signal describes a first period and a second period, the second period being shorter than the first period;

a prevention unit configured to prevent transmission of radio signals upon receiving the request signal; and

a transmitting unit configured to transmit radio signals to the radio base station during the first period according to the assignment signal received from the radio base station, and

the one radio terminal completes the transmission of the radio signals within the second period.

2. The terminal according to claim 1, wherein the second radio terminal ends transmission of the radio signal when the second period described in the assignment signal ends.

3. A radio base station, comprising:

a receiving unit configured to receive an access right request from a first radio terminal, the access right request identifies a first period and a second period; and

a transmitting unit configured to transmit an assignment signal to the first radio terminal and the second radio terminal, the first period and the second period being described in the assignment signal,

wherein the receiving unit receives radio signals transmitted from the first radio terminal and the second radio during the first period, and wherein transmission of the radio signals by the first radio terminal and the second radio terminal completes within the second period.

4. The station according to claim 3, wherein the second radio terminal cancels the prevention of transmission of radio signals and transmits radio signals according to the assignment signal even when transmission of radio signals is prevented according to receiving of the request signal directed to the radio base station, and

the first radio terminal transmits radio signals according to the assignment signal.

5. The station according to claim 3, wherein the request signal describes a duration during which transmission of radio signals to another radio terminal other than the first radio terminal is prevented,

a transmission period of radio signals by the first radio terminal is calculated based on the duration described in the request signal, and

the assignment signal describes the calculated transmission period of the radio signals by the first radio terminal as a period during which radio signals can be transmitted to the radio base station under the space multiplexing scheme.

6. The station according to claim 3, wherein when the receiving unit receives the request signals from a plurality of radio terminals, the receiving unit assumes that the request signal has been received from a radio terminal having a low frequency with which the access right has been given out of the plurality of radio terminals or a radio terminal having a longer time that has elapsed after being given the access right out of the plurality of radio terminals.

7. The station according to claim 3, wherein

the receiving unit receives the request signals from a plurality of radio terminals which can transmit radio signals to the radio base station under the space multiplexing scheme,

the request signals received from the plurality of radio terminals describe transmission periods of the radio signals requested by the plurality of radio terminals respectively, and

the assignment signal describes a longest period out of transmission periods of radio signals requested by the plurality of radio terminals as a period during which radio signals can be transmitted to the radio base station under the space multiplexing scheme.

8. A radio base station, comprising:

a receiving unit configured to receive, from a first radio terminal, a request signal for requesting an access right to transmit radio signals to the radio base station; and

a transmitting unit configured to transmit an assignment signal for assigning an access right to the first radio terminal and a second radio terminal, wherein an identifier of the second radio terminal is associated with the first radio terminal,

wherein the request signal describes a first period and a second period, the second period is shorter than the first period,

the assignment signal describes the first period and the second period,

the receiving unit receives radio signals from the first radio terminal and the second radio terminal during the first period; and

the first radio terminal and the second radio terminal complete transmission of the radio signals within the second period.

9. The station according to claim 8, further comprising a decision unit configured to decide, when the receiving unit receives a change request signal for requesting a change of the length of the second period from the first radio terminal or the second radio terminal during the first period, whether or not to change the length of the second period based on a current length of the second period and the length of the second period requested by the first radio terminal or the second radio terminal, which is the sender of the change request signal, and whether or not to change a group of radio terminals that receive radio signals under the space multiplexing scheme from a group including the first and second radio terminals to another group.

10. The station according to claim 9, wherein when the decision unit decides to change the length of the second period, the transmitting unit transmits a signal for reporting the changed second period to the first radio terminal and the second radio terminal, and

when the decision unit decides to change the group of radio terminals to the another group, the transmitting unit transmits a signal for reporting the changed second period to the another group.

11. The station according to claim 9, wherein when the receiving unit receives the change request signals from a plurality of radio terminals, the decision unit performs decision processing based on the length of the second period requested by a radio terminal already assigned the access right out of the plurality of radio terminals and the current length of the second period.

12. The station according to claim 9, wherein when the receiving unit receives the change request signals from a plurality of radio terminals, the decision unit performs decision processing based on the length of the second period requested by one radio terminal determined out of the plurality of radio terminals wherein the one radio terminal is determined according to reception situations of the radio signals from the plurality of radio terminals under the space multiplexing scheme.

13. The station according to claim 9, wherein when the receiving unit receives the change request signals from a plurality of radio terminals, the decision unit performs the decision processing based on a longest period of the second periods requested by the plurality of radio terminals or the length of the second period requested by a radio terminal having a maximum number of retransmissions out of the plurality of radio terminals.