Method for mapping downlink dedicated pilots to resource elements in extended cyclic prefix frame structure

• US 20100142476A1
• Filed: 12/25/2008
• Published: 06/10/2010
• Est. Priority Date: 03/20/2008
• Status: Active Grant

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: Yu, Guanghui, Yu, Hui, Jiang, Jing
• Granted Patent: US 8,391,233 B2
• Time in Patent Office: Days
• US Class Current: 370/330
• CPC Class Codes: H04B 7/068 using space frequency diversity space-frequency coding H04L1/0606
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal

Abstract

A method for mapping downlink dedicated pilot frequencies of an extend cyclic prefix frame structure to physical resource blocks, applied in a long term evolution system, includes the following steps: the first downlink dedicated pilot frequency of each channel is mapped to the specific position of a physical resource block; other downlink dedicated pilot frequencies of the channel are mapping-processed according to the time domain interval, frequency domain interval and the preset regulation; the time domain interval is two or three OFDM symbols, the frequency domain interval is two sub-carriers of the same time domain. By defining the positions of pilot frequencies in the physical resource block, the public pilot frequency can obtain the information of all channels when a base station uses a beam pattern of more than four antennas. Making the channel information obtained by dedicated pilot frequencies contain the real channel information and the process-weight-value of a beam pattern, a UE does not need to obtain the transmission-weight-value of a beam pattern, such as to avoid the feedback cost of weight-values of a beam pattern.

Claims

1. A method for mapping downlink dedicated pilots to resource elements in Extended Cyclic Prefix (Extended CP) frame structure, applied in a Long Term Evolution (LTE) system, comprising the following steps:

mapping the first downlink dedicated pilot of each port to the specific position of a physical resource block;

mapping-processing other downlink dedicated pilots of the port according to the time-domain interval, frequency-domain interval and the preset regulation; and

the time-domain interval being two or three Orthogonal Frequency Division Multiplexing symbols, and the frequency-domain interval being two subcarriers in the same time domain.

2. The mapping method according to claim 1, wherein, the preset regulation is:

12 subcarriers are mapped to the physical resource blocks in the frequency domain, while one port of four downlink dedicated pilots is mapped in the same time domain, and the dedicated pilots are two subcarriers apart from each other.

3. The mapping method according to claim 1, wherein, only one port of downlink dedicated pilots is transmitted in the physical resource block.

4. The mapping method according to claim 3, wherein, the corresponding time-domain position of the specific position is the 5^th orthogonal frequency division multiplexing symbol, and the corresponding frequency-domain position thereof is the same subcarrier of the first column of cell-specific reference signals in the physical resource block.

5. The mapping method according to claim 3, wherein, the physical resource block comprises twelve subcarriers in the frequency domain, and twelve orthogonal frequency division multiplexing symbols in the time domain, the mapping method comprises specifically:

mapping the first downlink dedicated pilot to the 5^th orthogonal frequency division multiplexing symbol in the time domain, and to the A^th subcarrier in the frequency domain;

mapping the second downlink dedicated pilot to the 5^th orthogonal frequency division multiplexing symbol in the time domain, and to the (A+3)^th subcarrier in the frequency domain;

mapping the third downlink dedicated pilot to the 5^th orthogonal frequency division multiplexing symbol in the time domain, and to the (A+6)^th subcarrier in the frequency domain;

mapping the fourth downlink dedicated pilot to the 5^th orthogonal frequency division multiplexing symbol in the time domain, and to the (A+9)^th subcarrier in the frequency domain;

mapping the fifth downlink dedicated pilot to the 8^th orthogonal frequency division multiplexing symbol in the time domain, and to the B^th subcarrier in the frequency domain;

mapping the sixth downlink dedicated pilot to the 8^th orthogonal frequency division multiplexing symbol in the time domain, and to the (B+3)^th subcarrier in the frequency domain;

mapping the seventh downlink dedicated pilot to the 8^th orthogonal frequency division multiplexing symbol in the time domain, and to the (B+6)^th subcarrier in the frequency domain;

mapping the eighth downlink dedicated pilot to the 8^th orthogonal frequency division multiplexing symbol in the time domain, and to the (B+9)^th subcarrier in the frequency domain;

mapping the ninth downlink dedicated pilot to the 12^th orthogonal frequency division multiplexing symbol in the time domain, and to the C^th subcarrier in the frequency domain;

mapping the tenth downlink dedicated pilot to the 12^th orthogonal frequency division multiplexing symbol in the time domain, and to the (C+3)^th subcarrier in the frequency domain;

mapping the eleventh downlink dedicated pilot to the 12^th orthogonal frequency division multiplexing symbol in the time domain, and to the (C+6)^th subcarrier in the frequency domain;

mapping the twelfth downlink dedicated pilot to the 12^th orthogonal frequency division multiplexing symbol in the time domain, and to the (C+9)^th subcarrier in the frequency domain;

wherein, B and C equal to 1 or 2 or 3.

6. The mapping method according to claim 1, wherein, there are multiple ports of downlink dedicated pilots in the physical resource block, and the specific time-domain positions to which each port of downlink dedicated pilots is mapped in the physical resource block are located at the 5^th orthogonal frequency division multiplexing symbol of the physical resource block, while the specific frequency-domain positions to which every port of downlink dedicated pilots is mapped in a physical resource block being staggered from one another.

7. The mapping method according to claim 3, wherein, the physical resource block comprises twelve subcarriers in the frequency domain, and twelve orthogonal frequency division multiplexing symbols in the time domain, and the mapping method comprises specifically:

dividing a port of twelve downlink dedicated pilots into three groups, each group comprising four downlink dedicated pilots that are located at the same orthogonal frequency division multiplexing symbol;

in the time domain, mapping the first group of downlink dedicated pilots to the 5^th orthogonal frequency division multiplexing symbol in the time domain;

mapping the second group of downlink dedicated pilots to the 8^th orthogonal frequency division multiplexing symbol in the time domain; and

mapping the third group of downlink dedicated pilots to the 11^th or 12^th orthogonal frequency division multiplexing symbol in the time domain;

in the frequency domain, mapping the 1^st one of 4 downlink dedicated pilots in each group to the 1^st or 2^nd or 3^rd subcarrier in the frequency domain, and mapping the 2^nd to 4^th downlink dedicated pilots to subcarriers that are two subcarriers apart from each other in order in the frequency domain.

8. The mapping method according to claim 3, wherein, the physical resource block comprises twelve subcarriers in the frequency domain, and twelve orthogonal frequency division multiplexing symbols in the time domain, and the mapping method comprises specifically:

dividing a port of twelve downlink dedicated pilots into three groups, each group comprising four downlink dedicated pilots that are located at the same orthogonal frequency division multiplexing symbol;

in the time domain, mapping the first group of downlink dedicated pilots to the 5^th orthogonal frequency division multiplexing symbol in the time domain;

mapping the second group of downlink dedicated pilots to the 9^th orthogonal frequency division multiplexing symbol in the time domain; and

mapping the third group of downlink dedicated pilots to the 12^th orthogonal frequency division multiplexing symbol in the time domain;

in the frequency domain, mapping the 1^st one of four downlink dedicated pilots in each group to the 1^st, 2^nd or 3^rd subcarrier in the frequency domain, and mapping the 2^nd to 4^th downlink dedicated pilots to subcarriers that are two subcarriers apart from each other in order in the frequency domain.

9. The mapping method according to claim 7, wherein:

the 1^st, 2^nd, 3^rd, 4^th downlink dedicated pilots are all mapped to the 5^th OFDM symbol in the time domain, and to the 1^st, 4^th, 7^th, 10^th subcarriers sequentially in the frequency domain;

the 5^th, 6^th, 7^th, 8^th downlink dedicated pilots are all mapped to the 8^th OFDM symbol in the time domain, and to the 1^st, 4^th, 7^th, 10^th subcarriers sequentially in the frequency domain, or to the 3^rd, 6^th, 9^th, 12^th subcarriers sequentially in the frequency domain;

the 9^th, 10^th, 11^th, 12^th downlink dedicated pilots are all mapped to the 11^th or 12^th OFDM symbol in the time domain, and to the 1^st, 4^th, 7^th, 10^th subcarriers sequentially in the frequency domain.

10. The mapping method according to claim 7, wherein:

the 1^st, 2^nd, 3^rd, 4^th downlink dedicated pilots are all mapped to the 5^th OFDM symbol in the time domain, and to the 1^st, 4^th, 7^th, 10^th subcarriers sequentially in the frequency domain;

the 5^th, 6^th, 7^th, 8^th downlink dedicated pilots are all mapped to the 8^th OFDM symbol in the time domain, and to the 2^nd, 5^th, 8^th, 11^th subcarriers sequentially in the frequency domain;

the 9^th, 10^th, 11^th, 12^th downlink dedicated pilots are all mapped to the 11^th or 12^th OFDM symbol in the time domain, and to the 3^rd, 6^th, 9^th, 12^th subcarriers sequentially in the frequency domain.

11. The mapping method according to claim 8, wherein:

the 1^st, 2^nd, 3^rd, 4^th downlink dedicated pilots are all mapped to the 5^th OFDM symbol in the time domain, and to the 1^st, 4^th, 7^th, 10^th subcarriers sequentially in the frequency domain;

the 5^th, 6^th, 7^th, 8^th downlink dedicated pilots are all mapped to the 9^th OFDM symbol in the time domain, and to the 3^rd, 6^th, 9^th, 12^th subcarriers sequentially in the frequency domain;

the 9^th, 10^th, 11^th, 12^th downlink dedicated pilots are all mapped to the 12^th OFDM symbol in the time domain, and to the 1^st, 4^th, 7^th, 10^th subcarriers sequentially in the frequency domain.

12. The mapping method according to claim 2, wherein, only one port of downlink dedicated pilots is transmitted in the physical resource block.

13. The mapping method according to claim 2, wherein, there are multiple ports of downlink dedicated pilots in the physical resource block, and the specific time-domain positions to which each port of downlink dedicated pilots is mapped in the physical resource block are located at the 5^th orthogonal frequency division multiplexing symbol of the physical resource block, while the specific frequency-domain positions to which every port of downlink dedicated pilots is mapped in a physical resource block being staggered from one another.