Radio apparatus

• US 20070064822A1
• Filed: 09/19/2006
• Published: 03/22/2007
• Est. Priority Date: 09/20/2005
• Status: Active Grant

• Current Assignee: Hera Wireless S.A. (Fineur International S.A.)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakao, Seigo
• Granted Patent: US 8,149,930 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 27/261 Details of reference signals
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/26132 using repetition
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601

Abstract

Among destination terminal apparatuses to which a plurality of data signals are to be transmitted, a control unit specifies a terminal apparatus to which a known signal, whose number of streams is greater than the number of streams for a data signal, is to be transmitted. The control unit appends a known signal, whose number of streams is greater than the number of streams for this data signal, to the data signal which is to be transmitted to the specified terminal apparatus. While assigning the data signal, to which the known signal has been appended, to a posterior part of the plurality of data signals, the control unit generates packet signals in a manner that a known signal, whose number of streams corresponds to the number of streams for a data signal in a header portion, is appended to a header portion of the plurality of data signals.

Claims

1. A radio apparatus for transmitting, in a predetermined period of time, to at least one terminal apparatus each of a plurality of data signals by at least one stream, the apparatus comprising:

an input unit which inputs the plurality of data signals;

a specifying unit which specifies a terminal apparatus to which known signals having the number of streams greater than that of data signals are to be transmitted, among terminal apparatuses to which the plurality of data signals inputted in said input unit are to be transmitted;

a generation unit which generates packet signals in a manner that;

the known signals having the number of streams greater than that of data signals are appended to the data signals which are to be transmitted to the terminal apparatus specified by said specifying unit, and

while the data signals to which the known signals have been appended are assigned to a rear part in the plurality of data signals, known signals having the number of streams corresponding to the number of streams of data signals in a leading part are appended to a leading part in the plurality of data signals; and

a transmitter which transmits a packet signal generated by said generation unit.

2. A radio apparatus according to claim 1, further comprising a receiving unit which receives a request indicating that a known signal having the number of streams greater than that of data signals needs to be transmitted,

wherein said specifying unit specifies a terminal apparatus corresponding to the request received by said receiving unit.

3. A radio apparatus according to claim 1, wherein said generation unit generates a plurality of packet signals from the plurality of data signals and has a data signal, to which a known signal is appended, contained in a posterior part of packet signal in the plurality of packet signals, and

wherein said transmitter transmits the plurality of packet signals generated by said generation unit, at an interval shorter than an interval at which a packet signal is to be transmitted normally.

4. A radio apparatus according to claim 1, wherein said generation unit generates a single packet in a form such that a plurality of data signals are aggregated.

5. A radio apparatus according to claim 1, wherein said generation is such that when known signals whose number of streams is greater than the number of data signals are appended, the known signals are appended to a main stream where a data signal is assigned and a sub-stream where no data signal is assigned, respectively, and a known signal in the sub-stream is assigned to a timing other than a timing to which a data signal and a known signal in the main stream are assigned.

6. A radio apparatus according to claim 5, wherein said generation unit is such that

using a known signal, as a reference, assigned to one of main streams, a cyclic timing shift within a known signal is applied to a known signal assigned to the other streams and a timing shift is also applied to an extensional known signal assigned to sub-streams,

degrees of priority are set beforehand to amounts of timing shift and, for the main streams, the amounts of timing shift are used, in order, from one having a higher degree of priority, and

for the sub-streams, the amounts of timing shift are used, in order, from one having a higher degree of priority.

7. A radio apparatus according to claim 5, wherein said generation unit is such that

using a known signal, as a reference, assigned to one of main streams, a cyclic timing shift within a known signal is applied to a known signal assign to the other streams and a timing shift is also applied to an extensional known signal assigned to sub-streams, and

different values of amounts of timing shift are set to the plurality of streams, respectively.

8. A radio apparatus according to claim 6, wherein in said generation unit the known signal and the extensional known signal are formed by repeating a predetermined unit in time domain,

a combination of signs of the predetermined unit is defined so that an orthogonality holds among the streams, and

the combination of signs of the predetermined unit is so defined as to be fixed in the plurality of streams, respectively.

9. A radio apparatus according to claim 6, wherein in said generation unit the known signal and the extensional known signal are formed by repeating a predetermined unit in time domain,

while a combination of signs of the predetermined unit is defined so that an orthogonality holds among the streams, a degree of priority is given beforehand to the combination of signs of the predetermined unit, and

for the main streams, combinations of signs are used in order, from one having a higher degree of priority and, for the sub-stream, combinations of signs are used in order, from one having a higher degree of priority.

10. A radio apparatus according to claim 6, wherein said generation unit is such that the cyclic timing shift is applied to a data signal, and an amount of timing shift for the main stream is used as the amount of timing shift.

11. A radio apparatus according to claim 6, further comprising a modification unit which modifies at least a data signal, to which the a known signal is appended, among the plurality of packet signals generated by said generation unit and outputs a modified signal to said transmitter,

said modification unit including:

a first processing unit which extends the number of main streams up to the number of a plurality of streams and then, for the extended stream, applies a cyclic timing shift within a known signal to a known signal assigned to the other streams using as a reference a known signal assigned to one of the extended streams; and

a second processing unit which extends the number of sub-streams up to the number of a plurality of streams and then, for the extended streams, applies a cyclic timing shift within an extensional known signal to an extensional known signal assigned to the other streams using as a reference an extensional known signal assigned to one of the extended streams,

wherein the amount of timing shift is set in a manner that the respective values of timing shift amounts used for the streams extended in the first processing unit are respectively equal to those for the streams extended in the second processing unit.

12. A radio apparatus according to claim 11, wherein an absolute value of the timing shift amount in said generation unit is so set as to be greater than that in said modification unit.