Method of transmitting data from a transmitter to a receiver, and a radio system

• US 20030022636A1
• Filed: 06/28/2002
• Published: 01/30/2003
• Est. Priority Date: 12/30/1999
• Status: Active Grant

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Horneman, Kari, Ylitalo, Juha, Juntti, Markku, Katz, Marcos
• Granted Patent: US 7,286,612 B2
• Time in Patent Office: Days
• US Class Current: 455/101
• CPC Class Codes: H04B 7/0613 using simultaneous transmission H04B7/0686 takes precedence
• CPC Class Codes: H04L 1/0048 in conjunction with detection of multiuser or interfering signals, e.g. iteration between CDMA or MIMO detector and FEC decoder for spatial equalizer H04L25/03286

Abstract

The invention relates to a method of transmitting data from a transmitter to a receiver in a radio system, and to a radio system. The method includes the following: channel-coding the data using selected channel-coding; dividing the channel-coded non-interleaved data into signals with different contents, to be transmitted via at least two different transmitter antennas; providing the signal to be transmitted via each transmitter antenna with an identifier, by means of which identifier the signals transmitted via different transmitter antennas are distinguishable from each other in the receiver; transmitting the signals to the receiver using different transmitter antennas; detecting the signal transmitted via each transmitter antenna with a receiver receiving each transmitter antenna in the receiver, and combining the detected signals into received channel-coded non-interleaved data; decoding the channel-coding of the received channel-coded non-interleaved data; and the receiver attenuating interference utilizing the decoded data.

Claims

1. A method of transmitting data from a transmitter to a receiver in a radio system, comprising:

channel-coding the data using selected channel-coding;

dividing the channel-coded non-interleaved data into signals with different contents, to be transmitted via at least two different transmitter antennas;

providing the signal to be transmitted via each transmitter antenna with an identifier, by means of which identifier the signals transmitted via different transmitter antennas are distinguishable from each other in the receiver;

transmitting the signals to the receiver using different transmitter antennas;

detecting the signal transmitted via each transmitter antenna with a receiver receiving each transmitter antenna in the receiver, and combining the detected signals into received channel-coded non-interleaved data;

decoding the channel-coding of the received channel-coded non-interleaved data; and

the receiver attenuating interference utilizing the decoded data.

2. A method according to claim 1, wherein the identifier is a spreading code used to spread the signal or a known reference symbol sequence added to the signal.

3. A method according to claim 1, wherein the number of transmitter antennas used in the transmission is dependent on the code rate of the channel-coding used.

4. A method according to claim 1, wherein the number of transmitter antennas used in the transmission is dependent on the constraint length of the channel-coding.

5. A method according to claim 1, wherein the transmitter antennas are spatial diversity antennas.

6. A method according to claim 1, wherein the transmitter antennas are polarization diversity antennas.

7. A method according to claim 1, wherein the transmitter antennas implementing angle diversity use directed antenna beams.

8. A method according to claim 1, wherein the code rate and the number of transmitter antennas are changed adaptively.

9. A method according to claim 8, further comprising:

increasing the transmission speed of the data to be transmitted by keeping the code rate the same and increasing the number of transmitter antennas.

10. A method according to claim 8, further comprising:

keeping the transmission speed of the data to be transmitted the same by reducing the code rate and correspondingly increasing the number of transmitter antennas.

11. A method according to claim 1, further comprising:

computing a quality value for the received signal of each transmitter antenna in the receiver;

transmitting the computed quality value or the control data formed on the basis of the quality value back to the transmitter; and

the transmitter making a decision on the transmission power of each transmitter antenna on the basis of the computed quality values or the control data.

12. A method according to claim 1, further comprising:

re-encoding the decoded data in the receiver using the channel-coding used in the transmission;

and for interference attenuation;

estimating multiple access interference for each transmitter antenna by utilizing the re-encoded data; and

cancelling the multiple access interference from the received signal of each transmitter antenna;

re-detecting with receivers the received signals of each transmitter antenna, purged from the multiple access interference; and

combining the detecting signals into received channel-coded non-interleaved data;

finally, decoding the channel-coding of the received channel-coded non-interleaved data.

13. A method according to claim 12, further comprising:

repeating the detection and combination of the signal, the decoding of the channel-coding of the received data, and the re-encoding, as well as the estimation and cancellation of the multiple access interference as many times as is required for cancelling the interference, or a predetermined number of times.

14. A method according to claim 12, further comprising:

performing the cancellation of the multiple access interference for selected multipath-propagated signal component of each transmitter antenna separately, or for a signal combined from the selected multipath-propagated signal components of each transmitter antenna, or for a signal combined from different transmitter antennas.

15. A method according claim 1, wherein in the receiver for interference attenuation:

a signal is received using at least two receiver antennas;

the interference signal in the signal of each receiver antenna is estimated;

weighting coefficients that maximize the signal to interference and noise ratio are formed for each receiver antenna;

and the signal of each receiver antenna is multiplied with the weighting coefficient.

16. A method according to claim 1, wherein in the receiver for interference attenuation:

the channel equalizer of the receiver is adjusted by utilizing the decoded data.

17. A radio system comprising a transmitter and a receiver connected to a transmitter, which transmitter comprises a channel encoder for channel-coding data and at least two transmitter antennas for transmitting the channel-coded data, and the receiver comprises a receiver per each transmitter antenna for detecting the signal transmitted via the transmitter antenna in question,

and the transmitter further comprises:

means for dividing the channel-coded non-interleaved data into signals with different contents, to be transmitted via at least two different transmitter antennas;

and means for providing the signal to be transmitted via each transmitter antenna with an identifier, by means of which identifier the signals transmitted via different transmitter antennas are distinguishable from each other in the receiver;

and the receiver further comprises;

means for combining the signals transmitted via different transmitter antennas into received, channel-coded non-interleaved data;

a channel decoder for decoding the channel-coding of the received channel-coded non-interleaved data;

and interference attenuation means for attenuating interference by utilizing the decoded data.

18. A radio system according to claim 17, wherein the identifier is a spreading code used for spreading a signal, or a known reference symbol sequence added to the signal.

19. A radio system according to claim 17, wherein the number of transmitter antennas used in the transmission depends on the code rate of the channel-coding used.

20. A radio system according to claim 17, wherein the number of transmitter antennas depends on the constraint length of the channel-coding used.

21. A radio system according to claim 17, wherein the transmitter antennas are spatial diversity antennas.

22. A radio system according to claim 17, wherein the transmitter antennas are polarization diversity antennas.

23. A radio system according to claim 17, wherein the transmitter antennas implement angle diversity by using directed antenna beams.

24. A radio system according to claim 17, wherein the transmitter comprises means for changing the code rate and the number of transmitter antennas adaptively.

25. A radio system according to claim 24, wherein when the code rate is kept the same and the number of transmitter antennas is increased, the transmission speed of the data to be transmitted is increased.

26. A radio system according to claim 24, wherein when the code rate is reduced and the number of transmitter antennas correspondingly increased, the transmission speed of the data to be transmitted is kept the same.

27. A radio system according to claim 17, wherein the receiver further comprises means for computing a quality value for the received signal of each transmitter antenna, and the transmitter comprises means for making a decision on the transmission power of each transmitter antenna on the basis of the computed quality values or the quality values of the receiver.

28. A radio system according to claim 17, wherein the receiver further comprises a channel encoder for re-encoding the decoded data by using the channel-coding used in the transmission;

and the interference attenuation means comprise;

estimating means for estimating multiple access interference for the received signal of each transmitter antenna by utilizing the re-encoded data;

interference cancellation means for cancelling the multiple access interference from the received signal of each transmitter antenna;

receivers for re-detecting the received signal of each transmitter antenna, purged from the multiple access interference;

means for re-combining the detected signals into received channel-coded non-interleaved data; and

a channel encoder for finally re-decoding the channel-coding of the received channel-coded non-interleaved data.

29. A radio system according to claim 28, wherein the receiver comprises a predetermined number of interference cancellation stages, which interference cancellation stage comprises receivers, means for combining the signals, channel decoders, channel encoders, estimating means, and interference cancellation means.

30. A radio system according to claim 28, wherein the interference cancellation means perform cancellation of the multiple access interference for selected multipath-propagated signal components of each transmitter antenna separately, or for a signal combined from the selected multipath-propagated signal components, or for a signal combined from different transmitter antennas.

31. A radio system according to claim 17, wherein the interference attenuation means of the receiver comprise:

at least two receiver antennas for receiving a signal;

means for estimating the interference signal in the signal of each receiver antenna;

means for forming for each receiver antenna weighting coefficients that maximize the signal to interference and noise ratio;

and means for multiplying the signal of each receiver antenna with the weighting coefficient.

32. A radio system according to claim 17, wherein the interference attenuation means of the receiver comprise:

a channel equalizer;

and means for adjusting the channel equalizer by utilizing the decoded data.