Method for estimating channel parameters of radio channels of a W-CDMA mobile radio system

1. A method for estimating channel parameters of radio channels of a W-CDMA mobile radio system, which comprises the steps of:

transmitting sequences of at subscriber side a priori known symbols before at subscriber side a priori unknown data symbols from a base station;

determining the last two sequences of known symbols transmitted before the data symbols;

carrying out a first channel estimation by comparing the last two received sequences of known symbols with the at subscriber side stored known symbols;

carrying out a second channel estimation by comparing a penultimate received sequence of known symbols with the at subscriber side stored known symbols;

carrying out an intexpolation between channel parameters derived from the first channel estimation and channel parameters derived from the second channel estimation; and

determining a hypothesis for the channel parameters for detecting the data symbols based on the interpolation.

2. The method according to claim 1 , which further comprises the step of performing the steps of claim 1 to determine a hypothesis for present channel parameters when a speed of movement of a mobile receiver is high and data rates of transmission are high.

3. A method for estimating channel parameters of radio channels of a W-CDMA mobile radio system, which comprises the steps of:

continuously transmitting a sequence of first at subscriber side a priori known symbols on a common channel (common pilot channel) from a base station to all subscribers;

transmitting sequences of second at subscriber side a priori known symbols chronologically between unknown data symbols on one or more subscriber-specific channels;

carrying out an estimation of the channel parameters for the one or more subscriber-specific channels with the at subscriber side stored second known symbols by comparing received second known symbols transmitted with the one or more subscriber-specific channels with the at subscriber side stored second known symbols;

carrying out an estimation of the channel parameters for the common channel by comparing received first known symbols continuously transmitted on the common channel with the at subscriber side stored first known symbols; and

correcting the estimation of the channel parameters for the one or more subscriber-specific channels while no second known symbols on the one or more subscriber-specific channels are transmitted corresponding to a change in the channel parameters for the common channel.

4. The method according to claim 3 , which further comprises the step of:

correcting the estimated channel parameters for the subscriber-specific channels according to the following formula:

ĥ d n+1 = ĥ d n +k·Δ ĥ p n+1 ,

wherein ĥ n represents an estimation of the channel pulse response of a respective subscriber-specific channel at a time n; Δ{circumflex over (n)} p n+1 represents a change in the estimation of the channel pulse response of the common channel from times n to time n+1; and k represents an adjustable correction factor.

5. The method according to claim 4 , wherein:

present indexing relates to a case in which the data-transmitting channel and the common pilot channel have the same spread factor; and

when there are different spread factors, the indexing is converted according to a ratio of spread factors.