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Adaptive pilot insertion for a MIMO-OFDM system

A technology of pilot symbols and additional pilots, which is applied in the field of transmission of pilot signals and signaling, can solve problems such as insufficient and achieve good performance

Active Publication Date: 2007-08-22
QUALCOMM INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this pilot structure may not be sufficient for certain receiving entities experiencing adverse channel conditions

Method used

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  • Adaptive pilot insertion for a MIMO-OFDM system
  • Adaptive pilot insertion for a MIMO-OFDM system
  • Adaptive pilot insertion for a MIMO-OFDM system

Examples

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Embodiment Construction

[0018] As used in this application, the word "exemplary" means "serving as an example, illustration or illustration". Any embodiment or design described herein as "exemplary" is not to be construed as preferred or advantageous over other embodiments or designs.

[0019] The pilot transmission and signaling techniques described in this application may be used in single-input single-output (SISO) systems, single-input multiple-output (SIMO) systems, multiple-input single-output (MISO) systems, and MIMO systems. These techniques can be used in OFDM systems and other multi-carrier communication systems. These techniques can also be used for various OFDM subband structures. For clarity, the techniques are described below specifically for a MIMO-OFDM system using the OFDM subband structure defined by IEEE 802.11a.

[0020] The IEEE 802.11 OFDM subband structure divides the entire system bandwidth into 64 orthogonal subbands (ie, K=64), and the indices assigned to these 64 orthogon...

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Abstract

A transmitting entity transmits a ''base'' pilot in each protocol data unit (PDU). A receiving entity is able to derive a sufficiently accurate channel response estimate of a MIMO channel with the base pilot under nominal (or most) channel conditions. The transmitting entity selectively transmits an additional pilot if and as needed, e.g., based on channel conditions and / or other factors. The additional pilot may be adaptively inserted in almost any symbol period in the PDU. The receiving entity is able to derive an improved channel response estimate with the additional pilot. The transmitting entity sends signaling to indicate that additional pilot is being sent. This signaling may be embedded within pilot symbols sent on a set of pilot subbands used for a carrier pilot that is transmitted across most of the PDU. The signaling indicates whether additional pilot is being sent and possibly other pertinent information.

Description

field of invention [0001] The present invention relates generally to communications and, more particularly, to techniques for transmitting pilot signals and signaling within a multiple-input multiple-output (MIMO) communication system. technical background [0002] For data transmission, a MIMO system uses multiple (T) transmit antennas at the transmitting entity and multiple (R) receive antennas at the receiving entity. A MIMO channel formed by T transmit antennas and R receive antennas can be decomposed into S spatial channels, where S≤min{T, R}. The S spatial channels may be used to transmit data in parallel to increase throughput and / or redundantly to increase reliability. [0003] Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier modulation technique that effectively divides the entire system bandwidth into multiple (K) orthogonal frequency subbands. These subbands are also called tones, subcarriers, bins, and frequency channels. With OFDM, each sub...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L25/02H04B7/04H04L27/26H04J99/00
CPCH04B7/0413H04L1/0001H04L27/261H04L25/0226H04L25/0204H04L1/06H04B1/76H04L27/2675H04L5/0048
Inventor 杰伊·罗德尼·沃尔顿马克·S.·华莱士
Owner QUALCOMM INC