Reference signal acquisition

Abstract

Various aspects of the disclosure relate to techniques associated with the acquisition of reference signals. In some aspects, a network may request a user equipment (UE) to measure a timing difference between neighbor cells and use that information to generate a CSI-RS configuration. The network sends the CSI-RS configuration to the UE to enable the UE to acquire a CSI-RS from a neighbor cell. In some aspects, a network may send timing-related information to a neighbor cell and the neighbor cell uses that information to transmit a CSI-RS.

What is claimed is: 
     
         1 . An apparatus for communication comprising:
 a memory device; and   a processing circuit coupled to the memory device and configured to:
 determine a timing difference between a first cell and a second cell; 
 send an indication of the timing difference to the first cell; 
 receive a channel state information-reference signal (CSI-RS) configuration that is based on the timing difference; and 
 decode a CSI-RS of the second cell based on the CSI-RS configuration. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the CSI-RS configuration comprises an indication that timing for the CSI-RS of the second cell is based on timing of the first cell, 
     
     
         3 . The apparatus of  claim 1 , wherein the CSI-RS configuration comprises an indication that timing for the CSI-RS of the second cell is based on timing of the second cell. 
     
     
         4 . The apparatus of  claim 1 , wherein the timing difference comprises a symbol timing difference, a slot timing difference, a mini-slot timing difference, or a system frame number timing difference. 
     
     
         5 . The apparatus of  claim 1 , wherein the CSI-RS configuration comprises the indication of the timing difference. 
     
     
         6 . The apparatus of  claim 1 , wherein the CSI-RS configuration comprises a scrambling identifier associated with the CSI-RS of the second cell. 
     
     
         7 . The apparatus of  claim 1 , wherein the CSI-RS configuration comprises a seed for obtaining a scrambling identifier associated with the CSI-RS of the second cell. 
     
     
         8 . The apparatus of  claim 1 , wherein the CSI-RS configuration comprises an indication that the CSI-RS of the second cell uses one scrambling sequence over a set of symbols. 
     
     
         9 . The apparatus of  claim 1 , wherein the CSI-RS configuration comprises an indication that the CSI-RS of the second cell uses different scrambling sequences over a set of symbols. 
     
     
         10 . The apparatus of  claim 9 , wherein the processing circuit is further configured to:
 test a plurality of sequence hypotheses over the set of symbols as a result of receiving the indication in the CSI-RS configuration.   
     
     
         11 . The apparatus of  claim 1 , wherein the processing circuit is further configured to:
 conduct a mobility operation associated with the second cell based on the CSI-RS of the second cell.   
     
     
         12 . A method of communication for an apparatus, comprising:
 determining a timing difference between a first cell and a second cell;   sending an indication of the timing difference to the first cell;   receiving a channel state information-reference signal (CSI-RS) configuration that is based on the timing difference; and   decoding a CSI-RS of the second cell based on the CSI-RS configuration.   
     
     
         13 . The method of  claim 12 , further comprising testing a plurality of sequence hypotheses over a set of symbols as a result of receiving the indication in the CSI-RS configuration. 
     
     
         14 . The method of  claim 12 , further comprising conducting a mobility operation associated with the second cell based on the CSI-RS of the second cell. 
     
     
         15 . An apparatus for communication comprising:
 a memory device; and   a processing circuit coupled to the memory device and configured to:
 determine a timing difference between a first cell and a second cell; 
 determine, based on the timing difference, a channel state information-reference signal (CSI-RS) configuration for a CSI-RS of the second cell; and 
 send the CSI-RS configuration to a user equipment served by the first cell, 
   
     
     
         16 . The apparatus of  claim 15 , wherein the CSI-RS configuration comprises an indication that timing for the CSI-RS of the second cell is based on timing of the first cell. 
     
     
         17 . The apparatus of  claim 15 , wherein the CSI-RS configuration comprises an indication that timing for the CSI-RS of the second cell is based on timing of the second cell. 
     
     
         18 . The apparatus of  claim 15 , wherein the timing difference comprises a symbol timing difference, a slot timing difference, a mini-slot timing difference, or a system frame number timing difference. 
     
     
         19 . The apparatus of  claim 15 , wherein the CSI-RS configuration comprises an indication of the timing difference. 
     
     
         20 . The apparatus of  claim 15 , wherein the CSI-RS configuration comprises an indication of the timing difference taking into account a sub-carrier spacing between the first cell and the second cell. 
     
     
         21 . The apparatus of  claim 15 , wherein the CSI-RS configuration comprises a scrambling identifier associated with the CSI-RS of the second cell. 
     
     
         22 . The apparatus of  claim 15 , wherein the CSI-RS configuration comprises a seed for obtaining a scrambling identifier associated with the CSI-RS of the second 
     
     
         23 . The apparatus of  claim 15 , wherein the CSI-RS configuration comprises an indication of whether the CSI-RS of the second cell uses one scrambling sequence or different scrambling sequences over a set of symbols. 
     
     
         24 . The apparatus of  claim 15 , wherein the processing circuit is further configured to receive an indication of the timing difference from the user equipment. 
     
     
         25 . The apparatus of  claim 15 , wherein the processing circuit is further configured to send a request to measure the timing difference to the user equipment. 
     
     
         26 . The apparatus of  claim 15 , wherein the processing circuit is further configured to:
 receive a first indication of the timing difference from the user equipment and at least one second indication of the timing difference from at least one other user equipment; and   generate an estimate of the timing difference based on the first indication of the timing difference and the at least one second indication of the timing difference,   
     
     
         27 . A method of communication for an apparatus, comprising:
 determining a timing difference between a first cell and a second cell;   determining, based on the timing difference, a channel state information-reference signal (CSI-RS) configuration for a CSI-RS of the second cell; and   sending the CSI-RS configuration to a user equipment served by the first cell.   
     
     
         28 . The method of  claim 27 , wherein the determining the timing difference comprises receiving an indication of the timing difference from the user equipment. 
     
     
         29 . The method of  claim 27 , further comprising sending a request to measure the timing difference to the user equipment. 
     
     
         30 . The method of  claim 27 , wherein the determining the timing difference comprises:
 receiving a first indication of the timing difference from the user equipment and at least one second indication of the timing difference from at least one other user equipment; and   generating an estimate of the timing difference based on the first indication of the timing difference and the at least one second indication of the timing difference.