Apparatus and method for transmitting/receiving pilot pattern set to distinguish base station in orthogonal frequency division multiplexing (OFDM) communication system

• US 7,436,758 B2
• Filed: 10/27/2004
• Issued: 10/14/2008
• Est. Priority Date: 10/27/2003
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ro, Jung-Min, Cho, Young-Kwon, Suh, Chang-Ho, Yoon, Seok-Hyun
• Primary Examiner(s): Jung; Min
• Application Number:
  US10/974,413
• Publication Number:
  US 20050088960A1
• Time in Patent Office: 1,448 Days
• Field of Search: 370/203, 370/208, 370/335, 370/342, 370/491
• US Class Current: 370/203
• CPC Class Codes: H04L 27/261 Details of reference signals
• CPC Class Codes: H04L 5/026 using code division

Abstract

An apparatus and method for transmitting/receiving a pilot pattern set to distinguish a base station in an FDM communication system. The method divides a total frequency bandwidth into at least two sub-bandwidths including a plurality of sub-carriers in an OFDMA (Orthogonal Frequency Division Multiple Access) mobile communication system, configures a single frame cell (FC) using one sub-bandwidth from among the sub-bandwidths and a plurality of OFDM (Orthogonal Frequency Division Multiplexing) symbol intervals, and assigns a pilot signal to a time-frequency cell comprised of at least one OFDM symbol and at least one sub-carrier within the FC. The method includes the steps of spreading a pilot signal and a data signal using different orthogonal codes, synthesizing the spread pilot and data signals, and performing a CDM (Code Division Multiplexing) process; and mapping the CDM-processed pilot and data signals to a predetermined time-frequency cell in the FC.

Claims

1. A method for mapping a pilot signal to a time-frequency cell in an OFDMA (Orthogonal Frequency Division Multiple Access) wireless communication system, in which the time-frequency cell includes at least one OFDM symbol and at least one sub-carrier within a signal frame cell (FC), a total frequency bandwidth of the OFDMA system is divided into at least one sub-bandwidth including a plurality of sub-carriers, and the FC includes one sub-bandwidth of the at least one sub-bandwidth and at least one OFDM symbol interval, the method comprising the steps of:

a) spreading a pilot signal using a first orthogonal code and a data signal using a second orthogonal code different from the first orthogonal code;

b) combining the spread pilot signal and the spread data signal; and

c) mapping the combined signal to a predetermined time-frequency cell in the FC.

2. The method according to claim 1, wherein the first orthogonal code is used to identify a BS (Base Station).

3. The method according to claim 1, wherein the combined signal is mapped to the time-frequency cell in the FC according to a predetermined pattern distinguishable by each BS.

4. The method according to claim 3, wherein the mapping pattern is determined by a slope of a time-frequency domain.

5. The method according to claim 4, wherein the slope is ‘

1’

, and is adapted to map the combined signal to all the time-frequency cells contained in the FC.

6. The method according to claim 1, wherein when the OFDMA wireless communication system includes a plurality of FCs, a plurality of orthogonal codes for pilot signals of the plurality of FCs are different from each other.

7. A method for distinguishing a Base Station (BS) by mapping a pilot signal to a time-frequency cell in an OFDMA (Orthogonal Frequency Division Multiple Access) wireless communication system, in which the time-frequency cell includes at least one OFDM symbol and at least one sub-carrier within a single frame cell (FC), a total frequency bandwidth of the OFDMA system is divided into at least one sub-bandwidth including a plurality of sub-carriers, and the FC includes one sub-bandwidth of the at least one sub-bandwidth and at least one OFDM symbol interval, the method comprising the steps of:

a) determining an orthogonal code for each FC such that the orthogonal code is used for a CDM (Code Division Multiplexing) signal processing according to a BSID (Base Station Identifier);

b) spreading a pilot signal for each FC using the determined orthogonal code, spreading a data signal to be transmitted using a code other than the determined orthogonal code;

c) combining the spread pilot signal and the spread data signal; and

d) mapping the combined signal to a predetermined time-frequency cell contained in the FC.

8. The method according to claim 7, wherein the orthogonal code is determined to identify a BS (Base Station).

9. The method according to claim 7, wherein the combined signal is mapped to the time-frequency cell in the FC according to a predetermined mapping pattern distinguishable by each BS.

10. The method according to claim 9, wherein the mapping pattern is determined by a slope of a time-frequency domain.

11. The method according to claim 10, wherein the slope is ‘

1’

, and is adapted to map the combined signal to all time-frequency cells contained in the FC.

12. A method for receiving a pilot signal mapped to a time-frequency cell in an OFDMA (Orthogonal Frequency Division Multiple Access) wireless communication system, in which the time-frequency cell includes at least one OFDM symbol and at least one sub-carrier within a single frame cell (FC), a total frequency bandwidth of the OFDMA system is divided into at least one sub-bandwidth including a plurality of sub-carriers, and the FC includes one sub-bandwidth of the at least one sub-bandwidth and at least one OFDM symbol interval, the method comprising the steps of:

a) performing an FFT (Fast Fourier Transform) processing of a reception signal for each FC, and despreading the FFT result using a plurality of orthogonal codes of pilot signals for distinguishing BSs; and

b) selecting an orthogonal code corresponding to a maximum value from among the despreading results

wherein the reception signal is generated by spreading the pilot signal using a first orthogonal code and a data signal using a second orthogonal code different from the first orthogonal code, combining the spread pilot signal and the spread data signal and mapping the combined signal to the time-frequency cell in the FC.

13. The method according to claim 12, further comprising the step of:

c) despreading the reception signal using at least one orthogonal code used for a CDM-signal processing in each FCs, and detecting the data signal.

14. The method according to claim 13, wherein the data signal is multiplexed with the pilot signal using the second orthogonal code other than the selected orthogonal code.

15. An apparatus for mapping a pilot signal to a time-frequency cell in an OFDMA (Orthogonal Frequency Division Multiple Access) wireless communication system, in which the time-frequency cell includes at least one OFDM symbol and at least one sub-carrier within a single frame cell (FC), a total frequency bandwidth of the an OFDMA wireless communication system is divided into at least one sub-bandwidth including a plurality of sub-carriers, and the FC includes one sub-bandwidth of the at least one sub-bandwidth and at least one OFDM symbol interval, the apparatus comprising:

a pilot code pattern set generator for determining a first orthogonal code for each FC, wherein the first orthogonal code is used to perform a CDM (Code Division Multiplexing) pilot signal processing according to a BSID (Base Station Identifier);

a pilot spread-spectrum unit for spreading the pilot signal using the first orthogonal code;

a data spread-spectrum unit for spreading a data signal using a second orthogonal code other than the first orthogonal code;

an adder for adding the pilot signal spread by the first orthogonal code and the data signal spread by the second orthogonal code in each FCs; and

an IFFT (Inverse Fast Fourier Transform) unit for mapping the added signal to a predetermined time-frequency cell contained in the FC.

16. The apparatus according to claim 15, wherein the first orthogonal code is adapted to identify a (Base Station(BS).

17. The apparatus according to claim 15, wherein the added signal is mapped to the time-frequency cell in the FC according to a predetermined mapping pattern distinguishable by each BS.

18. The apparatus according to claim 17, wherein the mapping pattern is determined by a slope of a time-frequency domain.

19. The apparatus according to claim 18, wherein the slope is ‘

1’

, and is adapted to map the combined signal to all the time-frequency cells contained in the FC.

20. An apparatus for mapping a pilot signal to a time-frequency cell in an OFDMA (Orthogonal Frequency Division Multiple Access) wireless communication system, in which the time-frequency cell includes at least one OFDM symbol and at least one sub-carrier within a single frame cell (FC), a total frequency bandwidth of the an OFDMA wireless communication system is divided into at least one sub-bandwidth including a plurality of sub-carriers, and the FC includes one sub-bandwidth of the at least one sub-bandwidth and at least one OFDM symbol interval, and receiving the assigned pilot signal, the apparatus comprising:

an FFT (Fast Fourier Transform) unit for performing an FFT process of a reception signal for each FC; and

a BS (Base Station) detector for despreading the reception signal using a plurality of orthogonal codes of pilots signals for distinguishing BS in order to select an orthogonal code corresponding to a maximum valued from among the despreading results

wherein the reception signal is generated by spreading the pilot signal using a first orthogonal code and a data signal using a second orthogonal code different from the first orthogonal code, combining the spread pilot signal and the spread data signal and mapping the combined signal to the time-frequency cell in the FC.

21. The apparatus according to claim 20, further comprising:

at least one data despreader for despreading the reception signal using at least one orthogonal code, used for a CDM process in the each FC, and detecting the data signal.

22. The apparatus according to claim 20, wherein the BS detector includes at least one maximum value detector for selecting the maximum valued to determine the orthogonal code having maximum valued from among the orthogonal codes.