Method and apparatus for estimating the link quality of a communication channel
AssigneeMediatek Incorporation
InventorMao-Ching Chiu
Life of this patent
Estimating the term…
Abstract
A link quality estimating method and apparatus adopts a fading value to modify an estimated link quality of a channel thereby obtaining a measure being very close to the real link quality. The method is implemented by utilizing two sequentially received long training symbols to derive two sets of subcarrier gain values Hk,1 and Hk,2. Based on the subcarrier gain values Hk,1 and Hk,2, parameters representing the estimated channel gain value (A), the fading value (F) and the noise quantity (B) of the channel are all calculable. With these parameters, the link quality (LQ) of said communication channel is derived.
Claims13
A method of estimating the link quality of a channel composed of subcarriers over which OFDM packets are transmitted, the method comprising the steps of:
- estimating a noise quantity (B) of said channel based on two long training symbols contained in a received OFDM packet transmitted over said channel;
- summing the absolute values of estimated subcarrier gain values (Hk) of said subcarriers thereby obtaining an estimated channel gain value (A) of said channel;
- estimating a fading value (F) of said channel based on said estimated subcarrier gain values;
- and
- subtracting said fading value (F) from said estimated channel gain value to derive a channel gain measure (A-F), whereby the link quality of said channel is defined as a ratio of the channel gain measure (A-F) to the noise quantity (B).
An apparatus for estimating the link quality of a channel composed of subcarriers, said apparatus comprising:
- channel gain estimating means for estimating a first and a second subcarrier gain values (Hk-1 Hk-2) for each subcarrier based on two sequentially received long training symbols of a received OFDM packet;
- calculating means for calculating a noise quantity (B), a fading value (F) and an estimated channel gain value (A) based on said first and second subcarrier gain values;
- and
- link quality calculating means for calculating the quality of said channel, wherein said link quality calculating means performs a subtraction of said fading value from said estimated channel gain value (A-F) to derive a modified channel gain value, whereby the quality of said channel is defined as a ratio of the modified channel gain value (A-F) to the noise quantity (B).
Dependencies are inferred from the claim text.