Channel estimate predicted from several previous channel estimates, for pre-equalization
A data transmission method includes transmitting an encoded data signal in form of a data stream of data bursts between a transmitter and a receiver, making a decision as a function of at least one data transmission parameter as to whether an interference treatment of the data signal to be transmitted will be performed in the transmitter or in the receiver, performing the interference treatment in terms of at least on code in the transmitter, and performing the interference treatment of the data to be transmitted in terms of at least one further code in the receiver.
1. A data transmission apparatus comprising a receiving device and a transmitting device,
wherein the receiving device comprises:
a channel estimator
a filter responsive to an input from the channel estimator and
a rake receiver responsive to an input from the channel estimator, and
wherein the transmitting device comprises
a modulator,
a preequalizer
a channel estimator, and
a decision making device, the decision making device being arranged to make a decision as to whether an interference treatment of a data signal to be transmitted is to be performed in the transmitter or not in response to a data transmission parameter selected from a rate of change of a channel estimate and a measure of the channel estimate,
the receiving device being arranged to provide the channel estimate to the transmitting device.
2. The apparatus of claim 1 , wherein the apparatus is a cellular code division multiple access system.
3. The apparatus of claim 1 , wherein the receiving device and the transmitting device are arranged to operate in a time division duplex mode.
4. The apparatus of claim 1 , wherein the channel estimate is a pulse function channel estimate.
5. The apparatus of claim 2 , wherein the interference treatment on the data to be transmitted is performed on one code and the receiving device is arranged to perform interference treatment on received data of at least one further code.
6. The apparatus of claim 1 , wherein the preequalizer is arranged to perform interference treatment using an extrapolated channel estimate derived from multiple channel pulse response estimates obtained over a period of time.
7. A transmitter being arranged to perform the steps of:
transmitting an encoded data signal in form of a data stream of data bursts;
making a decision in a decision making device as a function of at least one data transmission parameter as to whether an interference treatment of the data signal to be transmitted will be performed based on prior channel estimates;
in the event that interference treatment will be performed further performing the interference treatment on at least one coded channel; and
using as the at least one data transmission parameter on which the decision is made the at least one data transmission parameter which is a rate of change of an estimate of a pulse response of the data channel.
8. The transmitter as defined in claim 7 , wherein said transmitter is arranged to transmit the data signal as a CDMA-encoded data signal.
9. The transmitter as defined in claim 8 , wherein said transmitter is arranged to perform pre-distortion of codes of the data signal to be transmitted; and being further arranged to use for some codes a Dirac-pulse function as a channel estimate.
10. The transmitter as defined in claim 9 , wherein said transmitter is arranged to predict the channel estimate for the pre-equalization from a plurality of prior channel estimates.
11. The transmitter as defined in claim 10 , wherein said transmitter is arranged to calculate the channel estimate to be predicted from the prior channel estimates by linear extrapolation.