User equipment and evolved node-b and methods for operation in a coverage enhancement mode

Abstract

Embodiments of a User Equipment (UE) and an Evolved Node-B (eNB) and methods for operating in a coverage enhancement (CE) mode are generally described herein. The UE may include hardware processing circuitry configured to determine a CE category for the UE based at least partly on downlink channel statistics related to reception of one or more downlink signals from an eNB. The CE category may reflect one of a level of additional link margin and a level of system resources for performance at or above a performance threshold. The hardware processing circuitry may be further configured to transmit, in physical random access channel (PRACH) frequency resources, a PRACH preamble according to an uplink access repetition number. The PRACH frequency resources and the uplink access repetition number may be based at least partly on CE category for the UE.

What is claimed is: 
     
         1 . A User Equipment (UE) to operate in accordance with a coverage enhancement (CE) mode, the UE comprising hardware processing circuitry configured to:
 determine, from a group of candidate CE categories, a CE category for the UE based at least partly on downlink channel statistics related to reception of one or more downlink signals at the UE from an Evolved Node-B (eNB); and   transmit, in physical random access channel (PRACH) frequency resources, a PRACH preamble according to an uplink access repetition number;   wherein the PRACH frequency resources and the uplink access repetition number are based at least partly on the CE category for the UE.   
     
     
         2 . The UE according to  claim 1 , wherein the CE category for the UE reflects one of a level of additional link margin and a level of system resources for performance at or above a performance threshold associated with a normal operating mode for the UE. 
     
     
         3 . The UE according to  claim 1 , wherein the downlink channel statistics include reference signal received power (RSRP) or path loss measurements at the UE. 
     
     
         4 . The UE according to  claim 1 , wherein the group of candidate CE categories includes a first and a second candidate CE category for which an uplink access repetition number for the first CE category is different from an uplink access repetition number for the second CE category and PRACH frequency resources for the first CE category are exclusive to PRACH frequency resources for the second CE category. 
     
     
         5 . The UE according to  claim 1 , the hardware processing circuitry further configured to receive, from the eNB, a Random Access Response (RAR) according to a downlink repetition number that is based at least partly on the CE category for the UE. 
     
     
         6 . The UE according to  claim 5 , wherein:
 the RAR is received on physical downlink shared channel (PDSCH) frequency resources that are based at least partly on the CE category for the UE; and   the PDSCH frequency resources are disjoint from second PDSCH frequency resources for UEs not operating in the CE mode.   
     
     
         7 . The UE according to  claim 6 , wherein:
 the hardware processing circuitry is further configured to receive, from the eNB, a physical downlink control channel (PDCCH) data block on PDCCH frequency resources for UEs operating in the CE mode;   the PDCCH data block includes a downlink control information (DCI) block that includes the downlink repetition number.   
     
     
         8 . The UE according to  claim 6 , wherein the hardware processing circuitry is further configured to refrain from decoding physical downlink control channel (PDCCH) data blocks as part of the reception of the RAR. 
     
     
         9 . The UE according to  claim 5 , the hardware processing circuitry further configured to transmit, in response to the reception of the RAR, an uplink control message on physical uplink shared channel (PUSCH) resources according to an uplink control repetition number. 
     
     
         10 . The UE according to  claim 9 , wherein the RAR includes the uplink control repetition number. 
     
     
         11 . The UE according to  claim 10 , wherein the RAR includes an uplink grant for the UE and the uplink grant includes the uplink control repetition number. 
     
     
         12 . The UE according to  claim 9 , wherein:
 the uplink control message includes a second CE category for the UE;   the second CE category is selected from a second group of candidate CE categories; and   the second CE category is determined at least partly from the reception of the RAR.   
     
     
         13 . The UE according to  claim 9 , the hardware processing circuitry further configured to receive, from the eNB, a contention resolution message according to the downlink repetition number. 
     
     
         14 . The UE according to  claim 1 , wherein the UE is further to support Machine Type Communication (MTC) and to operate according to a 3GPP protocol. 
     
     
         15 . A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors to perform operations for communication by User Equipment (UE) in a coverage enhancement (CE) mode, the operations to configure the one or more processors to:
 determine, from a group of candidate CE categories, a CE category for the UE based at least partly on downlink channel statistics related to reception of one or more downlink signals at the UE from an Evolved Node-B (eNB); and   transmit, in physical random access channel (PRACH) frequency resources, a PRACH preamble according to an uplink access repetition number;   wherein the PRACH frequency resources and the uplink access repetition number are based at least partly on the CE category for the UE.   
     
     
         16 . The non-transitory computer-readable storage medium according to  claim 15 , the operations to further configure the one or more processors to receive, from the eNB, a Random Access Response (RAR) according to a downlink repetition number that is based at least partly on the CE category for the UE. 
     
     
         17 . The non-transitory computer-readable storage medium according to  claim 16 , the operations to further configure the one or more processors to transmit, in response to the reception of the RAR, an uplink control message on physical uplink shared channel (PUSCH) resources according to an uplink control repetition number that is based at least partly on the CE category for the UE. 
     
     
         18 . A method for communicating in a coverage enhancement (CE) mode performed by User Equipment (UE), the method comprising:
 determining, from a group of candidate CE categories, a CE category for the UE based at least partly on downlink channel statistics related to reception of one or more downlink signals at the UE from an Evolved Node-B (eNB); and   transmitting, in physical random access channel (PRACH) frequency resources, a PRACH preamble according to an uplink access repetition number;   wherein the PRACH frequency resources and the uplink access repetition number are based at least partly on the CE category for the UE.   
     
     
         19 . The method according to  claim 18 , further comprising receiving, from the eNB, a Random Access Response (RAR) according to a downlink repetition number that is based at least partly on the CE category for the UE. 
     
     
         20 . An Evolved Node-B (eNB) to operate in accordance with a coverage enhancement (CE) mode, the eNB comprising hardware processing circuitry configured to:
 receive, from a User Equipment (UE) operating in the CE mode, a physical random access channel (PRACH) preamble on PRACH frequency resources allocated for UEs operating in the CE mode;   determine, based at least partly on the PRACH frequency resources used for the reception of the PRACH preamble, a CE category for the UE from a group of candidate CE categories; and   transmit a Random Access Response (RAR) according to a downlink repetition number that is based at least partly on the CE category for the UE.   
     
     
         21 . The eNB according to  claim 20 , wherein the group of candidate CE categories includes a first and a second candidate CE category for which PRACH frequency resources for the first and second CE categories are exclusive. 
     
     
         22 . The eNB according to  claim 20 , wherein:
 the RAR is transmitted on physical downlink shared channel (PDSCH) frequency resources that are based at least partly on the CE category for the UE; and   the PDSCH frequency resources are disjoint from second PDSCH frequency resources for UEs not operating in a CE mode.   
     
     
         23 . The eNB according to  claim 22 , the hardware processing circuitry further configured to transmit a physical downlink control channel (PDCCH) data block that includes PDSCH resource allocations for UEs not operating in the CE mode and to refrain from transmission of PDCCH data blocks for UEs operating in the CE mode. 
     
     
         24 . The eNB according to  claim 22 , the hardware processing circuitry further configured to transmit a control message that includes an allocation for the PDSCH frequency resources, a modulation and coding scheme (MCS) indicator for the RAR transmission, and a timing relationship between PRACH transmission at the UE and the RAR transmission. 
     
     
         25 . The eNB according to  claim 20 , the hardware processing circuitry further configured to receive, from the UE, an uplink control message on physical uplink shared channel (PUSCH) resources according to an uplink control repetition number. 
     
     
         26 . The eNB according to  claim 25 , wherein the uplink control repetition number is based at least partly on the CE category for the UE. 
     
     
         27 . The eNB according to  claim 25 , wherein the RAR includes the uplink control repetition number. 
     
     
         28 . The eNB according to  claim 25 , the hardware processing circuitry further configured to transmit, in response to the reception of the uplink control message, a contention resolution message according to the downlink repetition number. 
     
     
         29 . The eNB according to  claim 20 , wherein:
 the hardware processing circuitry is further configured to receive, from a second UE not operating in the CE mode, a second PRACH preamble on second PRACH frequency resources allocated for UEs that are not operating in the CE mode; and   the second PRACH frequency resources are exclusive to the PRACH frequency resources allocated for UEs operating in the CE mode.   
     
     
         30 . The eNB according to  claim 20 , wherein the eNB is further to operate according to a 3GPP protocol.