Methods and arrangements for channel estimation

Abstract

Some embodiments provide a method for channel estimation in a wireless device. According to the method, the wireless device obtains an indication that a set of antenna ports, or antenna port types, share at least one channel property. The wireless device then estimates one or more of the shared channel properties based at least on a first reference signal received from a first antenna port included in the set, or having a type corresponding to one of the types in the set. Furthermore, the wireless device performs channel estimation based on a second reference signal received from a second antenna port included in the set, or having a type corresponding to one of the types in the set, wherein the channel estimation is performed using at least the estimated channel properties.

1 . A method for channel estimation in a wireless device, the method comprising:
 obtaining an indication that a set of antenna ports, or antenna port types, share at least one channel property;   estimating one or more of the shared channel properties based at least on a first reference signal received from a first antenna port included in the set, or having a type corresponding to one of the types in the set;   performing channel estimation based on a second reference signal received from a second antenna port included in the set, or having a type corresponding to one of the types in the set, wherein the channel estimation is performed using at least the estimated channel properties.   
     
     
         2 . The method of  claim 1 , wherein the estimation of one or more of the shared channel properties is performed jointly, based on the second reference signal and one or more additional reference signals received from respective antenna ports included in the set, or having a type corresponding to one of the types in the set. 
     
     
         3 . The method of  claim 2 , wherein the one or more additional reference signals comprise the first reference signal. 
     
     
         4 . The method of  claim 1 , wherein the step of performing channel estimation comprises:
 generating an estimation filter based on the estimated channel properties; and   applying the estimation filter to the second reference signal to obtain a channel estimate.   
     
     
         5 . The method of  claim 4 , further comprising applying the estimation filter to at least one other reference signal received from an antenna port included in the set, or having a type corresponding to one of the types in the set, to obtain a second channel estimate. 
     
     
         6 . The method of  claim 1 , wherein the indication indicates that the set of antenna ports or antenna port types can be considered to be co-located. 
     
     
         7 . The method of  claim 1 , wherein obtaining the indication comprises receiving a message from a network node. 
     
     
         8 . The method of  claim 7 , wherein the indication further indicates one or more resource block groups across which the set of antenna ports or antenna port types share at least one channel property, and wherein the estimation step is performed over the indicated resource block groups. 
     
     
         9 . The method of  claim 7 , wherein the indication further indicates a time interval during which the set of antenna ports or antenna port types share at least one channel property, and wherein the estimation step is performed during the indicated time interval. 
     
     
         10 . The method of  claim 1 , wherein obtaining the indication comprises determining the set of antenna ports or antenna port types based on a rule. 
     
     
         11 . The method of  claim 10 , wherein antenna ports whose reference signals are code multiplexed using an orthogonal cover code are considered to be part of the same set, and antenna ports whose reference signals are not code multiplexed using an orthogonal cover code are considered to be part of different sets. 
     
     
         12 . The method of  claim 1 , wherein the channel properties are one or more of: signal-to-noise ratio, delay spread, doppler spread, received timing, number of significant channel taps. 
     
     
         13 . A method in a network node, the method comprising:
 obtaining an indication that a set of antenna ports, or antenna port types, share at least one channel property; and   Transmitting signals corresponding to at least two of the antenna ports in the set, or antenna ports having types comprised in the set, from the same set of transmission points.   
     
     
         14 . The method of  claim 13 , further comprising transmitting an indication of the set of antenna ports, or antenna port types, to at least one wireless device served by the network node. 
     
     
         15 . The method of  claim 13 , wherein obtaining the indication comprises determining that antenna ports transmitting reference signals that are code multiplexed using an orthogonal cover code are part of the same set. 
     
     
         16 . The method of  claim 13 , wherein the indication is transmitted in system information, in an RRC message, or in downlink control information. 
     
     
         17 . The method according to  claim 16 , wherein the indication further indicates one or more resource block groups across which the set of antenna ports or antenna port types share at least one channel property, and wherein the network node transmits signals corresponding to at least two of the antenna ports in the set, or antenna ports having types comprised in the set, from the same set of transmission points over the indicated resource block groups. 
     
     
         18 . The method of  claim 16 , wherein the indication further indicates a time interval during which the set of antenna ports or antenna port types share at least one channel property, and wherein the network node transmits signals corresponding to at least two of the antenna ports in the set, or antenna ports having types comprised in the set, from the same set of transmission points during the indicated time interval. 
     
     
         19 . The method of  claim 13 , wherein the antenna port types correspond to types of reference signals transmitted by the ports, and comprise one or more of:
 DMRS, CSI-RS, CRS.   
     
     
         20 . A wireless device for performing channel estimation, the device comprising radio circuitry and processing circuitry, the processing circuitry further comprising a channel analyzer and a channel estimator, wherein
 the processing circuitry is configured to obtain an indication that a set of antenna ports, or antenna port types, share at least one channel property;   the channel analyzer is configured to estimate one or more of the shared channel properties based at least on a first reference signal transmitted from a first antenna port included in the set, or having a type corresponding to one of the types in the set, wherein the first reference signal is received via the radio circuitry;   the channel estimator is configured to perform channel estimation based on a second reference signal transmitted from a second antenna port included in the set, or having a type corresponding to one of the types in the set, wherein the channel estimation is performed using at least the estimated channel properties, and wherein the second reference signal is received via the radio circuitry.   
     
     
         21 . (canceled)