# US 2016/0366705 A1 · Random Access Procedures for Link Budget Constrained Wireless Devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2016/0366705 A1 - Document ID: US20160366705A1 - Status: Published application - Kind: A1 - Application number: 15/153,931 - Filed: 2016-05-13 - Published: 2016-12-15 - Earliest claimed: 2015-06-10 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Syed Aon Mujtaba; Tarik Tabet; Awais M. Hussain - Web page: https://patentgrep.com/patent/US20160366705A1 ## CPC - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network - H04W 72/51: based on terminal or device properties - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 74/002: {Transmission of channel access control information} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract This disclosure relates to accommodating link budget constrained wireless devices performing random access procedures. A base station may detect a preamble message from a wireless device. It may be determined that the preamble message is received from a link budget constrained wireless device. Characteristics of a response message may be selected based at least in part on determining that the preamble message is received from a link budget constrained wireless device. The response message may be transmitted to the link budget constrained wireless device using the selected characteristics. ## Claims ### Claim 1 A method for a base station configured to serve a cell, comprising: by the base station: detecting a preamble message on a physical random access channel; determining that the preamble message is received from a link budget constrained wireless device; selecting characteristics of a response message based at least in part on determining that the preamble message is received from a link budget constrained wireless device; and transmitting the response message to the link budget constrained wireless device using the selected characteristics. ### Claim 2 (depends on 1) The method of claim 1, wherein determining that the preamble message is received from a link budget constrained wireless device comprises determining that the preamble message does not meet a first correlation threshold and does meet a second correlation threshold, wherein the first correlation threshold is higher than the second correlation threshold. ### Claim 3 (depends on 1) The method of claim 1, wherein the characteristics of the response message are selected to increase the robustness of the response message. ### Claim 4 (depends on 1) The method of claim 1, wherein the characteristics of the response message comprise one or more of: an aggregation level of a control channel on which the response message is transmitted; a power level of control channel elements associated with the response message; or a modulation and coding scheme of the response message. ### Claim 5 (depends on 1) The method of claim 1, wherein the characteristics of the response message are selected to increase the robustness of a subsequent message from the link budget constrained wireless device to the base station. ### Claim 6 (depends on 1) The method of claim 1, wherein the characteristics of the response message comprise one or more of: a modulation and coding scheme grant for a subsequent message from the link budget constrained wireless device; or an indication to use transmission time interval bundling for the subsequent message from the link budget constrained wireless device. ### Claim 7 (depends on 1) The method of claim 1, further comprising: determining whether the link budget constrained device is at cell edge based on one or more of time of arrival or round trip delay of the preamble message, wherein the characteristics of the response message are selected further based on whether the link budget constrained device is at cell edge. ### Claim 8 A base station configured to serve a cell, comprising: a radio; and a processing element operably coupled to the radio, wherein the processing element and the radio are configured to: determine that a preamble message received from a wireless user equipment (UE) device on a physical random access channel does not meet a first correlation threshold and does meet a second correlation threshold, wherein the first correlation threshold is higher than the second correlation threshold; select characteristics of a response message transmitted to the UE device based on determining that the preamble message is does not meet the first correlation threshold and does meet the second correlation threshold; and transmit the response message to the UE device using the selected characteristics. ### Claim 9 (depends on 8) The base station of claim 8, wherein to select the characteristics of the response message, the processing element and the radio are further configured to select an aggregation level of a control channel on which the response message is transmitted, wherein a higher aggregation level is selected based on the preamble message not meeting the first correlation threshold than if the preamble message met the first correlation threshold. ### Claim 10 (depends on 8) The base station of claim 8, wherein to select the characteristics of the response message, the processing element and the radio are further configured to select a power level of control channel elements associated with the response message, wherein a higher power level is selected based on the preamble message not meeting the first correlation threshold than if the preamble message met the first correlation threshold. ### Claim 11 (depends on 8) The base station of claim 8, wherein to select the characteristics of the response message, the processing element and the radio are further configured to select a modulation and coding scheme of the response message, wherein a lower modulation and coding scheme is selected based on the preamble message not meeting the first correlation threshold than if the preamble message met the first correlation threshold ### Claim 12 (depends on 8) The base station of claim 8, wherein the response message comprises an indication of a modulation and coding scheme grant for a connection request message to be transmitted by the UE device, wherein to select the characteristics of the response message, the processing element and the radio are further configured to select the modulation and coding scheme grant, wherein a lower modulation and coding scheme grant is selected based on the preamble message not meeting the first correlation threshold than if the preamble message met the first correlation threshold. ### Claim 13 (depends on 8) The base station of claim 8, wherein to select the characteristics of the response message, the processing element and the radio are further configured to select to provide an indication to use transmission time interval bundling for a connection request message to be transmitted by the UE device based on the preamble message not meeting the first correlation threshold. ### Claim 14 (depends on 8) The base station of claim 8, wherein the processing element and the radio are further configured to: receive an indication in a connection request message received from the UE device that the UE device is link budget constrained; and select further communication characteristics with the UE device based at least in part on the indication that the UE device is link budget constrained. ### Claim 15 (depends on 8) The base station of claim 8, wherein the processing element and the radio are further configured to: estimate whether the preamble message does not meet the first correlation threshold because the UE device is at cell edge or because the UE device is hardware constrained based at least in part on lag in cross-correlation of the preamble message. ### Claim 16 An integrated circuit (IC) comprising a processing element configured to cause a wireless device to: transmit a preamble message to a base station on a physical random access channel; receive a random access response message from the base station; and transmit a radio resource control (RRC) connection request using information from the random access response message, wherein the RRC connection request indicates that the wireless device is link budget constrained. ### Claim 17 (depends on 16) The IC of claim 16, wherein the RRC connection request indicates that the wireless device is link budget constrained by including a RRC information element (IE) indicating that the wireless device is link budget constrained. ### Claim 18 (depends on 16) The IC of claim 16, wherein the RRC connection request indicates that the wireless device is link budget constrained by including a media access control (MAC) control element (CE) indicating that the wireless device is link budget constrained. ### Claim 19 (depends on 16) The IC of claim 16, wherein the random access response message indicates to use transmission time interval bundling for the radio resource control connection request, wherein transmitting the radio resource control connection request uses transmission time interval bundling. ### Claim 20 (depends on 16) The IC of claim 16, wherein the random access response message provides a temporary cell radio network temporary identifier (TC-RNTI) designated for use with link budget constrained devices to the wireless device, wherein one or more characteristics of the RRC connection request are selected based at least in part on the TC-RNTI being designated for use with link budget constrained devices.