Method and system for interference averagingin a wireless communication system

• US 20020085641A1
• Filed: 06/21/2001
• Published: 07/04/2002
• Est. Priority Date: 12/29/2000
• Status: Abandoned Application

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Baum, Kevin L.
• Application Number:
  US09/886,628
• Publication Number:
  US 20020085641A1
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0015 characterised by the adaptation strategy
• CPC Class Codes: H04L 1/04 using frequency diversity
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 5/0044 allocation of payload

Abstract

A family of methods for interference averaging in orthogonal frequency division multiplexing (OFDM) systems is provided. The methods can provide interference averaging in situations where an interfering co-channel is either partially or fully loaded. For partially loaded systems, subcarrier puncturing, frequency domain repetition, time domain repetition, and hybrid time-frequency repetition schemes are provided. For systems using adaptive modulation/coding rates, lower rates and transmit power can be selected in order to perform interference averaging in time-spread and frequency-spread OFDM schemes. In systems with downlink power control, frequency domain mixing can be used to perform interference averaging.

Claims

1. A method of interference averaging in a multicarrier system, comprising:

providing a plurality of subcarriers;

transmitting nulls on selected ones of the subcarriers during a symbol period; and

transmitting data on the remainder of the subcarriers during the symbol period.

2. The method of claim 1, further comprising:

spacing the nulls evenly on the subcarriers across a channel band.

3. The method of claim 1, further comprising:

randomly spacing the nulls on the subcarriers across a channel band.

4. The method of claim 1, further comprising:

offsetting the subcarriers in time.

5. The method of claim 1, further comprising:

offsetting the subcarriers in frequency.

6. A transmitter capable of interference averaging in a multicarrier system, comprising:

means for transmitting packet data on plurality of subcarriers;

means for transmitting nulls on selected ones of the subcarriers during a symbol period; and

means for transmitting data on the remainder of the subcarriers during the symbol period.

7. A method of interference averaging in a multicarrier system, comprising:

providing a plurality of subcarriers;

assigning a plurality of data symbols to a first subset of the subcarriers for transmission during a symbol period;

assigning the data symbols to a second subset of the subcarriers

for transmission during the symbol period; and

reducing the symbol transmit power as a function of at least one repeated data symbol in the symbol period.

8. The method of claim 7, further comprising:

assigning the at least one repeated data symbol to an adjacent subcarrier.

9. The method of claim 7, further comprising:

rotating the at least repeated data symbol by a predetermined value.

10. The method of claim 7, further comprising:

assigning the data symbols according to a predetermined cell repetition mapping.

11. The method of claim 7, further comprising:

offsetting the subcarriers in time.

12. The method of claim 7, further comprising:

offsetting the subcarriers in frequency.

13. A transmitter capable of interference averaging in a multicarrier system, comprising:

means for assigning a plurality of data symbols to a first subset of the subcarriers for transmission during a symbol period;

means for assigning the data symbols to a second subset of the subcarriers

for transmission during the symbol period; and

means for reducing the symbol transmit power as a function of at least one repeated data symbol in the symbol period.