US 11,751,238 B2
System and method for beam-based physical random-access
Mattias Frenne, Uppsala (SE); Håkan Andersson, Linköping (SE); Johan Furuskog, Stockholm (SE); Stefan Parkvall, Bromma (SE); Henrik Sahlin, Mölnlycke (SE); and Qiang Zhang, Täby (SE)
Assigned to TELEFONAKTIEBOLAGET LM ERICSSON (PUBL), Stockholm (SE)
Filed by Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
Filed on Sep. 2, 2020, as Appl. No. 17/9,912.
Application 17/009,912 is a continuation of application No. 16/395,461, filed on Apr. 26, 2019, granted, now 10,779,323.
Application 16/395,461 is a continuation of application No. 15/725,755, filed on Oct. 5, 2017, granted, now 10,433,335.
Application 15/725,755 is a continuation of application No. 14/400,579, granted, now 9,814,068, previously published as PCT/SE2014/050986, filed on Aug. 27, 2014.
Claims priority of provisional application 61/970,145, filed on Mar. 25, 2014.
Prior Publication US 2020/0404702 A1, Dec. 24, 2020
This patent is subject to a terminal disclaimer.
Int. Cl. H04W 72/04 (2023.01); H04W 74/00 (2009.01); H04B 7/08 (2006.01); H04W 72/044 (2023.01); H04B 7/0408 (2017.01); H04B 7/06 (2006.01); H04W 16/28 (2009.01); H04L 5/00 (2006.01)
CPC H04W 74/008 (2013.01) [H04B 7/0408 (2013.01); H04B 7/0617 (2013.01); H04B 7/086 (2013.01); H04L 5/0048 (2013.01); H04W 16/28 (2013.01); H04W 72/046 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A method in a wireless device for performing random access to a network node, the method comprising:
receiving a set of downlink beam-specific reference signals (BRSs) from the network node;
determining a preferred BRS based on the received signal power for each BRS in the set; and
selecting, based on the preferred BRS, a random-access preamble for transmitting a random-access attempt to the network node according to one or more pre-defined association rules defining an association between a random-access resource and a BRS, the selecting using a function that uses the preferred BRS as an input and provides the selected random-access preamble as an output, the function being specified in a standard; and
transmitting the selected random-access preamble to the network node, whereby the selection of the random-access preamble indicates to the network node which downlink beam is preferred by the wireless device to be used for downlink transmissions.