Beam change

Abstract

Method, apparatus, and computer program product for a user equipment to receive a downlink control information message from an access point in a wireless communications network and to echo a new beam index in the PUCCH feedback resource in response to the message indicating a PUCCH feedback resource and containing a beam change indication or in response to the message indicating a downlink grant containing a beam change indication MAC control element but no CSI-feedback is scheduled for the PUCCH feedback resource. If a scheduling request resource is indicated by the message or the MAC control element, the user equipment is triggered to transmit a scheduling request on that indicated scheduling request resource. If a scheduling request resource is not indicated by the message or the MAC control element, the user equipment is triggered to perform a scheduling request procedure on a periodic scheduling request resource.

1 - 21 . (canceled) 
     
     
         22 . An apparatus, comprising:
 at least one processor; and   at least one memory including computer program code,
 the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to: 
   receive, by a user equipment from an access point in a wireless communications network, a downlink control information message; and   in response to
 the message indicating a physical uplink control channel feedback resource and comprising a beam change indication wherein no medium access control, MAC, layer data is granted, or 
 the message indicating a downlink grant, wherein the downlink grant is decoded by the user equipment to detect a beam change indication MAC control element transmitted by the network, and no channel state information, CSI, -feedback is scheduled for the physical uplink control channel feedback resource, 
   echo a new beam index by the user equipment in the physical uplink control channel feedback resource.   
     
     
         23 . The apparatus of  claim 22 , wherein the beam change indication comprises an indication of a new serving beam different from a currently used serving beam by the access point for either downlink transmission or uplink reception. 
     
     
         24 . The apparatus of  claim 22 , wherein the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to in response to the message or a MAC control element indicating a scheduling request resource, trigger by the user equipment transmission of a scheduling request on the indicated scheduling request resource. 
     
     
         25 . The apparatus of  claim 24 , wherein the scheduling request is transmitted using the new serving beam. 
     
     
         26 . The apparatus of  claim 24 , wherein the scheduling request is triggered regardless of other scheduling request triggers. 
     
     
         27 . The apparatus of  claim 22 , wherein the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to when the message or a MAC control element does not indicate a scheduling request resource, in response to the detection of the beam change indication MAC control element, trigger a scheduling request procedure on a periodic scheduling request resource. 
     
     
         28 . The apparatus of  claim 22 , wherein when the message indicates the physical uplink control channel feedback resource, the physical uplink control channel feedback resource scheduled by the network is allocated with a size of at least one beam reported by the user equipment. 
     
     
         29 . The apparatus of  claim 22 , wherein the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus further to report by the user equipment a current serving beam to the access point. 
     
     
         30 . The apparatus of  claim 29 , wherein reporting by the user equipment the current serving beam informs the network whether the user equipment changed the beam. 
     
     
         31 . The apparatus of  claim 24 , wherein the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus further to upon receiving an uplink resource by triggering the scheduling request, generate by the user equipment a beam state information report. 
     
     
         32 . The apparatus of  claim 22 , wherein the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus further to trigger the receiving by sending a beam change request by the user equipment to the network. 
     
     
         33 . The apparatus of  claim 32 , wherein the beam change request comprises a preferred network communication beam index or a beam state information report. 
     
     
         34 . The apparatus of  claim 22 , wherein the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus further to:
 in response to the user equipment receiving or detecting the beam change indication, wherein the user equipment has not previously reported beam state information for N measurement periods of a beam reference signal, where N is configurable, transmit a scheduling request on a scheduling request resource if indicated in the message or trigger a scheduling request procedure if no scheduling request resource is indicated in the message, to report the beam state information.   
     
     
         35 . The apparatus of  claim 22 , wherein the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus further to:
 in response to the user equipment receiving or detecting the beam change indication, wherein a new serving beam belongs to a different beam group than a current serving beam, transmit a scheduling request on a scheduling request resource if indicated in the message or trigger a scheduling request procedure if no scheduling request resource is indicated in the message, to validate a group change using the new serving beam.   
     
     
         36 . The apparatus of  claim 35 , wherein groups are reported by the user equipment. 
     
     
         37 . The apparatus of  claim 35 , wherein groups are determined by reception direction of the user equipment. 
     
     
         38 . The apparatus of  claim 35 , wherein changing the serving beam in a group does not change beam alignment of the user equipment. 
     
     
         39 . A method comprising:
 receiving, by a user equipment from an access point in a wireless communications network, a downlink control information message; and   in response to
 the message indicating a physical uplink control channel feedback resource and comprising a beam change indication wherein no medium access control, MAC, layer data is granted, or 
 the message indicating a downlink grant, wherein the downlink grant is decoded by the user equipment to detect a beam change indication MAC control element transmitted by the network, and no channel state information, CSI, -feedback is scheduled for the physical uplink control channel feedback resource, 
   echoing a new beam index by the user equipment in the physical uplink control channel feedback resource.   
     
     
         40 . The method of  claim 39 , wherein the beam change indication comprises an indication of a new serving beam different from a currently used serving beam by the access point for either downlink transmission or uplink reception. 
     
     
         41 . A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the following:
 receiving, by a user equipment from an access point in a wireless communications network, a downlink control information message; and   in response to
 the message indicating a physical uplink control channel feedback resource and comprising a beam change indication wherein no medium access control, MAC, layer data is granted, or 
 the message indicating a downlink grant, wherein the downlink grant is decoded by the user equipment to detect a beam change indication MAC control element transmitted by the network, and no channel state information, CSI, -feedback is scheduled for the physical uplink control channel feedback resource, 
   echoing a new beam index by the user equipment in the physical uplink control channel feedback resource.