# US 2020/0288503 A1 · Random access procedure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0288503 A1 - Document ID: US20200288503A1 - Status: Published application - Kind: A1 - Application number: 16/764,174 - Filed: 2018-11-09 - Published: 2020-09-10 - Earliest claimed: 2017-11-16 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Henrik SAHLIN; Claes TIDESTAV; Andres REIAL; Icaro L. J. DA SILVA; Johan AXNÄS - Web page: https://patentgrep.com/patent/US20200288503A1 ## CPC - H04W 16/28: using beam steering - H04B 7/06966: {using beam correspondence; using channel reciprocity, e.g. downlink beam training based on uplink sounding reference signal [SRS]} - H04B 7/06968: {using quasi-colocation [QCL] between signals} - H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals} - H04W 72/04: Wireless resource allocation - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04L 5/0025: {Spatial division following the spatial signature of the channel} - H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals} - H04W 74/0838: using contention-free random access [CFRA] - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract According to certain embodiments, a method performed by a wireless device comprises initiating a random access procedure in which the wireless device sends a Physical Random Access Channel, PRACH, preamble to a network node and applying a receiver configuration for receiving an access response. The receiver configuration is determined based at least in part on whether a many-to-one association exists between (a) a downlink signal that can be used for beam selection prior to initiating the random access procedure, and (b) PRACH preamble indices. ## Claims ### Claim 1 A method performed by a wireless device, the method comprising: initiating a random access procedure in which the wireless device sends a Physical Random Access Channel, PRACH, preamble to a network node; and applying a receiver configuration for receiving an access response, the receiver configuration determined based at least in part on whether a many-to-one association exists between (a) a downlink signal that, prior to the initiating the random access procedure, can be used for beam selection, and (b) PRACH preamble indices. ### Claim 2 (depends on 1) The method of claim 1, wherein the downlink signal that can be used for beam selection comprises a Synchronization Signal Block, and/or a Channel State Information-Reference Signal. ### Claim 3 (canceled) ### Claim 4 (depends on 1) The method of claim 1, wherein, when a one-to-one association exists between the downlink signal and the PRACH preamble indices, the receiver configuration assumes quasi co-location between the downlink signal and the access response, and/or wherein, when a one-to-many association exists between the downlink signal and the PRACH preamble indices, the receiver configuration does not assume quasi co-location between the downlink signal and the access response. ### Claim 5 (canceled) ### Claim 6 (depends on 4) The method of claim 4, wherein the receiver configuration that does not assume quasi co-location between the downlink signal and the access response uses: beam scanning to detect the access response, or a wider beam for the reception of the access response compared to the receiver configuration that assumes quasi co-location between the downlink signal and the access response. ### Claim 7 (canceled) ### Claim 8 (depends on 1) The method of claim 1, wherein, when the many-to-one association exists between the downlink signal and the PRACH preamble indices, the receiver configuration is determined based on assuming a spatial correspondence between the access response and the PRACH preamble sent during the random access procedure. ### Claim 9 (depends on 1) The method of claim 1, wherein the determination whether the many-to-one association exists is based on at least one of: broadcast information received from the network while the wireless device is idle or inactive, and dedicated signalling received from the network while the wireless device is connected, wherein the dedicated signalling comprises any one of: a release message received via radio resource control signalling, or a handover command received via radio resource control signalling. ### Claim at position 10 10-12. (canceled) ### Claim 13 (depends on 1) The method of claim 1, further comprising configuring receive weights for receiving the access response to be the same as receive weights used for receiving the downlink signal on a preferred beam based on the downlink signal and the PRACH preamble indices having a one-to-one association. ### Claim 14 (depends on 1) The method of claim 1, further comprising configuring receive weights for receiving the access response to be different than receive weights used for receiving the downlink signal on a preferred beam based the downlink signal and the PRACH preamble indices having the many-to-one association. ### Claim 15 A wireless device, comprising: processing circuitry; and power supply circuitry configured to supply power to the wireless device; wherein the processing circuitry is configured to: initiate a random access procedure in which the wireless device sends a Physical Random Access Channel, PRACH, preamble to a network node; and apply a receiver configuration for receiving an access response, the receiver configuration determined based at least in part on whether a many-to-one association exists between (a) a downlink signal that, prior to initiating the random access procedure, can be used for beam selection, and (b) PRACH preamble indices. ### Claim at position 14 16-28. (canceled) ### Claim 29 A method performed by a base station, the method comprising: transmitting information to a wireless device, the information indicating whether a many-to-one association exists between (a) a downlink signal that the wireless device can use for beam selection prior to a random access procedure, and (b) physical random access channel, PRACH, preamble indices; transmitting one or more of the downlink signals that the wireless device can use for beam selection prior to the random access procedure; receiving a PRACH preamble from the wireless device; applying a transmitter configuration for transmitting an access response to the received PRACH preamble, the transmitter configuration based at least in part on whether a many-to-one association exists and on the received PRACH preamble. ### Claim 30 (depends on 29) The method of claim 29, wherein the downlink signal that can be used for beam selection comprises a Synchronization Signal Block, and/or a Channel State Information-Reference Signal. ### Claim 31 (canceled) ### Claim 32 (depends on 29) The method of claim 29, wherein, when a one-to-one association exists between the downlink signal and the PRACH preamble indices, the transmitter configuration applies quasi co-location to the downlink signal and the access response, and/or wherein, when the many-to-one association exists between the downlink signal and the PRACH preamble indices, the transmitter configuration does not apply quasi co-location between the downlink signal and the access response. ### Claim 33 (canceled) ### Claim 34 (depends on 32) The method of claim 32, wherein the transmitter configuration that does not apply quasi co-location between the downlink signal and the access response uses beam sweeping over all beams that map to the received PRACH preamble. ### Claim 35 (depends on 29) The method of claim 29, wherein, when the many-to-one association exists between the downlink signal and the PRACH preamble indices, the transmitter configuration transmits with spatial correspondence between the access response and the received PRACH preamble. ### Claim 36 (depends on 29) The method of claim 29, wherein the information is sent to the wireless device via at least one of broadcast messaging and dedicated signalling, wherein the dedicated signalling comprises: a release message sent via radio resource control signalling, or a handover command sent via radio resource control signalling. ### Claim at position 23 37-39. (canceled) ### Claim 40 (depends on 29) The method of claim 29, wherein when the many-to-one association exists, a beam used for transmitting the access response is different from any of the beams that map to the received PRACH. ### Claim 41 (depends on 29) The method of claim 29, wherein the different beam comprises a wide, cell-covering, or approximately isotropic beam. ### Claim 42 (depends on 29) The method of claim 29, wherein the information transmitted to the wireless device indicates the many-to-one association exists between the downlink signal and the PRACH preamble indices, but the method actually transmits the downlink signal according to a one-to-one association with the PRACH preamble indices. ### Claim 43 (depends on 29) The method of claim 29, further comprising configuring the transmitter to use TX precoding weights (2010) Universal when transmitting the access response, wherein the TX precoding weights are the same as TX precoding weights that were applied for transmitting the downlink signal indicated by the received PRACH preamble resources if the mapping between the downlink signal and the PRACH preamble indices comprises a one-to-one association, and/or that focus the access response energy in the direction of the PRACH reception if the mapping between the downlink signal and the PRACH preamble indices comprises the many-to-one association. ### Claim 44 (canceled) ### Claim 45 A base station, comprising: processing circuitry; and power supply circuitry configured to supply power to the network node; wherein the processing circuitry is configured to: transmit information to a wireless device, the information indicating whether a many-to-one association exists between (a) a downlink signal that the wireless device can use for beam selection prior to a random access procedure, and (b) physical random access channel, PRACH, preamble indices; transmit one or more of the downlink signals that the wireless device can use for beam selection prior to the random access procedure; receive a PRACH preamble from the wireless device; apply a transmitter configuration for transmitting an access response to the received PRACH preamble, the transmitter configuration based at least in part on whether a many-to-one association exists and on the received PRACH preamble. ### Claim at position 30 46-60. (canceled)