Radio communication apparatus and subcarrier assignment method

• US 7,522,544 B2
• Filed: 08/20/2004
• Issued: 04/21/2009
• Est. Priority Date: 08/20/2003
• Status: Active Grant

• Current Assignee: Panasonic Holdings Corporation
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Nishio, Akihiko, Cheng, Jun
• Primary Examiner(s): Kincaid; Lester
• Assistant Examiner(s): MITCHELL, NATHAN A
• Application Number:
  US10/568,673
• Publication Number:
  US 20060246916A1
• Time in Patent Office: 1,705 Days
• Field of Search: 455/23, 455/42, 370/343, 370/480
• US Class Current: 370/310
• CPC Class Codes: H04B 7/0621 Feedback content
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0042 intra-user or intra-terminal allocation
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0057 Physical resource allocation for CQI
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 64/003 locating network equipment
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

Wireless communication apparatus capable of improving communication efficiency by reducing the amount of control information transmitted is disclosed. With this apparatus, channel quality information extraction section (103) extracts CQI'"'"'s from a received signal. Allocation control section 104 allocates subcarriers every communication terminal apparatus and selects a modulation scheme in such a manner that required transmission rate is satisfied for each communication terminal apparatus based on required transmission rate information etc. and CQI'"'"'s for communication terminal apparatus of each user. Required subcarrier number determining section (105) decides the number of subcarriers allocated every communication terminal apparatus in such a manner as to satisfy the required transmission rate for each communication terminal apparatus based on required transmission rate information etc. of communication terminal apparatus of each user. Required subcarrier number information generating section (107) generates information for the number of subcarriers allocated every communication terminal apparatus. Subcarrier allocation section (110) allocates packet data to selected subcarriers. Modulating sections (111-1 to 111-N) adaptively modulate packet data allocated to each subcarrier.

Claims

1. A wireless communication apparatus comprising:

a subcarrier number determining section that determines the number of subcarriers to allocate to every communicating party;

a first transmission section that transmits information about the number of subcarriers determined in the subcarrier number determining section, to said every communicating party; and

an allocation control section that selects subcarriers to allocate transmission data for said every communicating party based on channel quality information of the number of subcarriers for said every communicating party extracted from a received signal,

wherein, when a sum of the amount of data of the channel quality information about the subcarriers selected by the communicating party and the amount of subcarrier identification information indicating the subcarriers selected by the communicating party is larger than the amount of data of channel quality information about all subcarriers in a communication band, the subcarrier number determining section determines the number of said all subcarriers in the communication band as the number of subcarriers to allocate to the communicating party.

2. The wireless communication apparatus according to claim 1, wherein the subcarrier number determining section determines the number of subcarriers to allocate to said every communicating party to achieve a required transmission rate of said every communicating party or more.

3. The wireless communication apparatus according to claim 1, wherein:

the subcarrier determining section determines the number of subcarriers for a communicating party by multiplying the number of subcarriers allocated to the communicating party by the allocation control section in one frame previous to a current frame, by a predetermined constant; and

the first transmission section transmits, in the current frame, information about the number of subcarriers determined in the subcarrier number determining section.

4. The wireless communication apparatus according to claim 1, wherein the subcarrier number determining section determines the number of subcarriers in accordance with equation (1) :

S_k=┌

α

×

R_k/r┐

 

 

(1)

where S_k;

the number of subcarriers (where k is a user number that is a natural number of 2 or more),

α

;

a first constant,

R_k;

a required transmission rate of communicating party (where k is a user number that is a natural number of 2 or more),

r;

a transmission rate for one subcarrier while employing modulation coding schemes having a highest transmission rate or a transmission rate for one subearrier while using modulation coding schemes satisfying a required packet error rate using a channel quality value of a value that is a sum of an average signal to noise ratio and a second constant, and

┌

α

×

R_k/r┐

;

a minimum integer equal to or larger than (α

×

R_k/r).

5. The wireless communication apparatus according to claim 1, wherein the subcarrier number determining section determines the number of subcarriers in accordance with equation (2)

S_k=┌

(β

×

R_k×

N)/(R₁+R₂+ . . . +R_k)┐

 

 

(2)

where S_k;

the number of subcarriers (where k is a user number that is a natural number of 2 or more),

β

;

a constant,

R_k;

a required transmission rate of the communicating party (where k is a user number that is a natural number of 2 or more)

N;

a total number of subcarriers, and

┌

(β

×

R_k×

N)/(R₁+R₂+ . . . +R_k)┐

;

a minimum integer equal to or larger than ((β

×

R_k×

N)/(R₁+R₂+ . . . +R_k)).

6. A communication terminal apparatus that communicates with the wireless communication apparatus according to claim 1, the communication terminal apparatus comprising:

a subcarrier selection section that selects subcarriers of the number of subcarriers in order of good reception quality using information about the number of subcarriers extracted from a received signal;

a channel quality information generating section that generates the channel quality information of the subcarriers selected in the subcarrier selection section; and

a second transmission section that transmits the channel quality information generated in the channel quality information generating section.

7. A base station apparatus comprising the wireless communication apparatus according to claim 1.

8. A subcarrier allocation method comprising the steps of:

determining the number of subcarriers to allocate to every communicating party;

transmitting information about the number of subcarriers determined in the step of determining the number of the subcarriers, to said every communicating party; and

selecting subcarriers to allocate transmission data for said every communicating party based on channel quality information of the number of subcarriers for said every communicating party extracted from a received signal,

wherein, in the step of determining the number of subcarriers to allocate to said every communicating party, when a sum of the amount of data of the channel quality information about the subcarriers selected by the communicating party and the amount of subcarrier identification information indicating the subcarriers selected by the communicating party is larger than the amount of data of channel quality information about all subcarriers in a communication band, the number of said all subcarriers in the communication band is determined as the number of subcarriers to allocate to the communicating party.

9. The subcarrier allocation method according to claim 8, wherein, in the step of determining the number of subcarriers to allocate to said every communicating party, the number of subcarriers to allocate to said every communicating party is determined to achieve a required transmission rate of said every communicating party or more.

10. The subcarrier allocation method according to claim 8, wherein:

the number of subcarriers for a communicating party is determined by multiplying the number of subcarriers to allocate to the communicating party in one frame previous to the current frame, by a predetermined constant; and

information about the determined number of subcarriers is transmitted in the current frame.