APPARATUS AND METHOD FOR TRANSMISSION/RECEPTION IN RADIO COMMUNICATION SYSTEM

• US 20150289281A1
• Filed: 01/28/2014
• Published: 10/08/2015
• Est. Priority Date: 01/28/2013
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Tae-Young, Seol, Ji-Yun, Yu, Hyun-Kyu
• Granted Patent: US 9,603,156 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0619 using feedback from receiving side feedback signaling for adaptive modulation/coding H04L1/0001
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

A transmitter, a receiver, and a method for measuring a radio channel based on reference signals transmitted through a predetermined number of OFDM symbols by using multiple antennas in an ultra-high frequency band, and controlling a beam width of analog beams formed by transmission multiple antennas based on the measurement result. The transmitter uniquely distributes a predetermined number of analog beams among the analog beams formed by the array antenna in correspondence to each of the predetermined number of OFDM symbols, and repeatedly allocates the predetermined number of analog beams distributed for each of the predetermined number of OFDM symbols by targeting the subcarriers within the corresponding OFDM symbol. The receiver receives a channel measurement instruction message, measures a channel state based on reference signals transmitted through the analog beams allocated for respective subcarriers, and feeds the channel state measurement result back to the transmitter.

Claims

1. A method of transmitting reference signals by a transmitter in a communication system, the method comprising:

allocating locations of subcarriers for respective analog beams to transmit the reference signals within a predetermined number of OFDM symbols; and

simultaneously transmitting, using an array antenna configured with a plurality of antenna elements, the reference signals using the analog beams corresponding to the subcarriers at at least two contiguous locations on a time axis or a frequency axis among the allocated locations.

2. The method of claim 1, wherein allocating the locations comprises:

uniquely distributing a predetermined number of analog beams among the analog beams formed by the array antenna in correspondence to each of the predetermined number of OFDM symbols; and

repeatedly allocating the predetermined number of analog beams distributed for each of the predetermined number of OFDM symbols by targeting the subcarriers within a corresponding OFDM symbol.

3. The method of claim 1, further comprising:

determining the at least two contiguous locations on the time axis or the frequency axis for determining at least two analog beams to simultaneously transmit the reference signals based on feedback information from a receiver.

4. The method of claim 3, wherein a maximum number of analog beams capable of simultaneously transmitting the reference signals is determined such that a maximum beam width for transmission of the reference signals is obtained.

5. The method of claim 1, wherein allocating the locations comprises:

allocating the locations of the subcarriers for the respective analog beams to transmit the reference signals by a symbol index assigned to each of the predetermined number of OFDM symbols and a subcarrier index assigned to each of the subcarriers within an OFDM symbol.

6. The method of claim 5, wherein the symbol index (t_i[k]) is determined by

7. The method of claim 5, wherein the symbol index (t_i[k]) is determined by {L+(−

1)^subi[k]·

(n_i mod L)−

(sub_i[k] mod

     2)} mod L and the subcarrier index (sub_i[k]) is determined based on

8. The method of claim 1, further comprising:

configuring a channel measurement instruction message to include resource allocation identification information, transmission method identification information, and beam index bitmap information; and

transmitting the configured channel measurement instruction message to a receiver through a downlink control channel,

wherein the resource allocation identification information comprises information for designating one of a wideband transmission method by which resources for transmission of the reference signals are dispersed and allocated within an entire frequency band, and a sub-band transmission method by which resources for transmission of the reference signals are allocated within a specific frequency band, wherein the transmission method identification information comprises information for guiding whether the reference signals are transmitted using one analog beam or a plurality of analog beams based on a pre-coder, and wherein the beam index bitmap information comprises information for designating an analog beam for which channel measurement is to be performed.

9. A method of reporting a channel measurement result by a receiver in a communication system, the method comprising:

receiving reference signals through analog beams corresponding to subcarriers at at least two contiguous locations on a time axis or a frequency axis among locations of the subcarriers allocated for the respective analog beams designated within a predetermined number of OFDM symbols;

measuring channels based on the received reference signals; and

feeding a result of the channel measurement back to a transmitter.

10. The method of claim 9, further comprising:

determining analog beams through which the reference signals are to be received, based on instruction information contained in a channel measurement instruction message received from the transmitter.

11. The method of claim 10, wherein:

the instruction information comprises resource allocation identification information, transmission method identification information, and beam index bitmap information,

the resource allocation identification information comprises information for designating one of a wideband transmission method by which resources for transmission of the reference signals are dispersed and allocated within an entire frequency band, and a sub-band transmission method by which resources for transmission of the reference signals are allocated within a specific frequency band,

the transmission method identification information comprises information for guiding whether the reference signals are transmitted using one analog beam or a plurality of analog beams based on a pre-coder, and

the beam index bitmap information comprises information for designating an analog beam for which channel measurement is to be performed.

12. The method of claim 11, wherein measuring the channels comprises:

identifying, using the beam index bitmap information, an index of an analog beam for which the channel measurement is to be performed;

measuring the channels based on a reference signal detected at a location of a subcarrier corresponding to the identified index of the analog beam from the predetermined number of received OFDM symbols; and

performing the channel measurement targeted at an entire frequency band or a specific frequency band based on the resource allocation identification information and the transmission method identification information and estimating a channel quality by a mean value of the measurement result values.

13. The method of claim 11, wherein measuring the channels comprises:

identifying, using the beam index bitmap information, an index of an analog beam for which the channel measurement is to be performed;

measuring the channels based on a reference signal detected at a location of a subcarrier corresponding to the identified index of the analog beam from the predetermined number of received OFDM symbols;

estimating a channel vector by channel measurement targeted on an entire frequency band or a specific frequency band based on the resource allocation identification information and the transmission method identification information;

determining a code-book index having a highest correlation with the estimated channel vector; and

estimating a mean channel quality in the entire frequency band or the specific frequency band in applying a pre-coder corresponding to the determined code-book index.

14. A transmitter for transmitting reference signals in a communication system, the transmitter comprising:

a resource allocating unit configured to allocate locations of subcarriers for respective analog beams to transmit the reference signals within a predetermined number of OFDM symbols; and

a transmission unit configured to simultaneously transmit, using an array antenna configured with a plurality of antenna elements, the reference signals using the analog beams corresponding to the subcarriers at at least two contiguous locations on a time axis or a frequency axis among the allocated locations.

15. The transmitter of claim 14, wherein the resource allocating unit is configured to uniquely distribute a predetermined number of analog beams among the analog beams formed by the array antenna in correspondence to each of the predetermined number of OFDM symbols, and repeatedly allocates the predetermined number of analog beams distributed for each of the predetermined number of OFDM symbols by targeting the subcarriers within a corresponding OFDM symbol.

16. The transmitter of claim 14, wherein the resource allocating unit is configured to determine the at least two contiguous locations on the time axis or the frequency axis for determining at least two analog beams to simultaneously transmit the reference signals based on feedback information from a receiver.

17. The transmitter of claim 16, wherein the resource allocating unit is configured to determine a maximum number of analog beams capable of simultaneously transmitting the reference signals to obtain a maximum beam width for transmission of the reference signals.

18. The transmitter of claim 14, wherein the resource allocating unit is configured to allocate the locations of the subcarriers for the respective analog beams to transmit the reference signals by a symbol index assigned to each of the predetermined number of OFDM symbols and a subcarrier index assigned to each of the subcarriers within an OFDM symbol.

19. The transmitter of claim 18, wherein the resource allocating unit is configured to determine the symbol index (t_i[k]) by

20. The transmitter of claim 18, wherein the resource allocating unit is configured to determine the symbol index (t_i[k]) by {L+(−

1)^subi[k]·

(n_i mod L)−

(sub_i[k] mod

     2)} mod L and the subcarrier index sub_i[k] by

21. The transmitter of claim 14, wherein the transmission unit is configured to configure a channel measurement instruction message to include resource allocation identification information, transmission method identification information, and beam index bitmap information;

and transmit the configured channel measurement instruction message to a receiver through a downlink control channel,

wherein the resource allocation identification information comprises information for designating one of a wideband transmission method by which resources for transmission of the reference signals are dispersed and allocated within an entire frequency band, and a sub-band transmission method by which resources for transmission of the reference signals are allocated within a specific frequency band, wherein the transmission method identification information comprises information for guiding whether the reference signals are transmitted using one analog beam or a plurality of analog beams based on a pre-coder, and wherein the beam index bitmap information comprises information for designating an analog beam for which channel measurement is to be performed.

22. A receiver for reporting a channel measurement result in a communication system, the receiver comprising:

a reception unit configured to receive reference signals through analog beams corresponding to subcarriers at at least two contiguous locations on a time axis or a frequency axis among locations of the subcarriers allocated for the respective analog beams designated within a predetermined number of OFDM symbols;

a channel measuring unit configured to measure channels based on the received reference signals; and

a transmission unit configured to feed a result of the channel measurement back to a transmitter.

23. The receiver of claim 22, wherein the reception unit is configured to determine analog beams through which the reference signals are to be received based on instruction information contained in a channel measurement instruction message received from the transmitter.

24. The receiver of claim 23, wherein:

the instruction information comprises resource allocation identification information, transmission method identification information, and beam index bitmap information,

the resource allocation identification information comprises information for designating one of a wideband transmission method by which resources for transmission of the reference signals are dispersed and allocated within an entire frequency band, and a sub-band transmission method by which resources for transmission of the reference signals are allocated within a specific frequency band,

the transmission method identification information comprises information for guiding whether the reference signals are transmitted using one analog beam or a plurality of analog beams based on a pre-coder, and

the beam index bitmap information comprises information for designating an analog beam for which channel measurement is to be performed.

25. The receiver of claim 24, wherein the channel measuring unit is configured to identify, using the beam index bitmap information, an index of an analog beam for which the channel measurement is to be performed;

measure a channel based on a reference signal detected at a location of a subcarrier corresponding to the identified index of the analog beam from the predetermined number of received OFDM symbols; and

perform the channel measurement targeted at an entire frequency band or a specific frequency band based on the resource allocation identification information and the transmission method identification information to estimate a channel quality by a mean value of the measurement result values.

26. The receiver of claim 24, wherein the channel measuring unit is configured to identify, the beam index bitmap information, an index of an analog beam for which the channel measurement is to be performed;

measure the channel based on a reference signal detected at a location of a subcarrier corresponding to the identified index of the analog beam from the predetermined number of received OFDM symbols;

estimate a channel vector by channel measurement targeted on an entire frequency band or a specific frequency band based on the resource allocation identification information and the transmission method identification information;

determine a code-book index having a highest correlation with the estimated channel vector; and

estimate a mean channel quality in the entire frequency band or the specific frequency band in applying a pre-coder corresponding to the determined code-book index.