8-transmit antenna reference signal design for downlink communications in a wireless system

1. A method of mapping reference signals for antenna ports in a plurality of resource blocks within an orthogonal frequency division multiplexing (OFDM) communication system, the method comprising:

selecting a plurality of resource elements for transmitting in the plurality of resource blocks using a first number of antenna ports, wherein the first number of antenna ports are used to transmit a first number of reference signals using at least one specified mapping scheme, and wherein the resource elements comprise a first number of OFDM symbols that are transmitted using the first number of antenna ports;

estimating, at a receiver, the first number of OFDM symbols to obtain a plurality of preceding vectors;

selecting a second number of antenna ports; and

mapping a plurality of reference signals relating to the second number of antenna ports using a second number of OFDM symbols, wherein each of the reference signals for the second number of antenna ports are mapped in one of the resource elements comprising each of the second number of OFDM symbols; and

estimating the second number of OFDM symbols transmitted from the second number of antenna ports using the precoding vectors from the first number of OFDM symbols that were transmitted from the first number of antenna ports.

2. The method of claim 1 , further comprising selecting the at least one predetermined resource element is selected according to at least one Long Term Evolution (LTE) standard.

3. The method of claim 1 , further comprising staggering a position of reference signal symbols of each of the second number of antenna ports in a subcarrier domain and in an OFDM-symbol domain.

4. The method of claim 3 , wherein the second number of antenna ports comprises an even number.

5. The method of claim 3 , wherein the staggering comprises mapping the reference signal symbols in identical subcarriers of each of the second number of OFDM symbols.

6. The method of claim 3 , wherein the staggering comprises mapping reference signal symbols in different subcarriers, wherein position differences are identical among the subcarriers including reference signals in each of the second number of OFDM symbols.

7. The method of claim 5 , wherein a number of the identical subcarriers is less than or equal to the second number of reference signals.

8. The method of claim 1 , wherein the method is performed in subframes not comprising synchronization signals.

9. The method of claim 1 , wherein the method is performed in resource blocks not comprising synchronization signals.

10. A system comprising:

a processor configured to map a plurality of reference signals for a number of antenna ports in a plurality of resource blocks within an orthogonal frequency division multiplexing (OFDM) communication system, the processor further configured to:

select resource elements for transmitting in the plurality of resource blocks using a first number of antenna ports, wherein the first number of antenna ports are used to transmit a first number of the reference signals using at least one specified mapping scheme, and wherein resource elements comprises a first number of OFDM symbols that are transmitted using the first number of antenna ports;

estimate the first number of OFDM symbols to obtain a plurality of precoding vectors;

select a second number of antenna ports; and

map a second number of the reference signals relating to the second number of antenna ports using a second number of OFDM symbols, wherein the reference signals for the second number of antenna ports are mapped in the resource elements comprising each of the second number of OFDM symbols;

estimate the second number of OFDM symbols transmitted from the second number of antenna ports using the precoding vectors from the first number of OFDM symbols that were transmitted from the first number of antenna; and

a transmitter configured to transmit the signals created by the processor over the plurality of antenna ports.

11. The system of claim 10 , wherein the resource elements are selected according to at least one Long Term Evolution (LTE) standard.

12. The system of claim 10 , wherein the processor is configured to stagger a position of reference signal symbols of each of the second number of antenna ports in a subcarrier domain and in an OFDM-symbol domain.

13. The system of claim 12 , wherein the second number of antenna ports comprises an even number.

14. The system of claim 12 , wherein the processor is configured to stagger the position of the reference signal symbols by mapping the reference signal symbols in identical subcarriers of each of the second number of OFDM symbols.

15. The system of claim 12 , wherein the processor is configured to stagger the position of the reference signal symbols by mapping reference signal symbols in different subcarriers, wherein position differences are identical among the subcarriers including reference signals in each of the second number of OFDM symbols.

16. The system of claim 14 , wherein a number of the identical subcarriers is less than or equal to the second number of reference signals.

17. The system of claim 10 , wherein the processor is configured to select a first number of subcarriers, wherein the first number of subcarriers is greater than the first number of antenna ports.

18. The system of claim 16 , wherein the processor is configured to map the first number of reference signals according to an LTE mapping scheme.

19. The system of claim 10 , wherein the processor is configured to perform the selecting, estimating, selecting, mapping, and estimating in subframes not comprising synchronization signals.

20. The system of claim 10 , wherein the processor is configured to perform the selecting, estimating, selecting, mapping, and estimating in resource blocks not comprising synchronization signals.