Random Access Coverage Enhancement Level Ramp Up Procedure

Abstract

In one embodiment, a method in a user equipment (UE) for random access (RA) coverage enhancement (CE) is disclosed. The method includes transmitting a random access preamble to a UE, wherein a power of the random access preamble is determined, in part, by a current CE level. The method further includes incrementing a value of a counter by one, wherein the value of the counter indicates a number of random access preambles previously transmitted by the UE. The method may then compare the value of the counter after incrementing its value, to a transmission limit, wherein the transmission limit indicates a maximum number of random access preamble transmission attempts for the current CE level. In response to the counter being equal to the transmission limit plus one, the method includes resetting the value of the counter.

1 . A method in a user equipment (UE) for random access coverage enhancement (CE), the method comprising:
 transmitting a random access preamble, wherein a power of the random access preamble is determined, in part, by a current CE level;   incrementing a value of a counter by one, wherein the value of the counter indicates a number of random access preambles previously transmitted by the UE;   comparing the value of the counter, after incrementing its value, to a transmission limit, wherein the transmission limit indicates a maximum number of random access preamble transmission attempts for the current CE level; and   in response to the counter being equal to the transmission limit plus one, resetting the value of the counter.   
     
     
         2 . The method of  claim 1 , wherein in response to the counter being equal to the transmission limit plus one, the method further comprises ramping up to the next CE level. 
     
     
         3 . The method of  claim 2 , wherein prior to ramping up to the higher CE level, the method further comprises:
 determining that the UE supports the higher CE level; and   determining that the higher CE level is supported by a cell, wherein the UE is transmitting the random access preamble from within a coverage area of the cell.   
     
     
         4 . The method of  claim 1 , wherein in response to the value of the counter being less than the transmission limit, the method further comprises increasing the power of the random access preamble. 
     
     
         5 . The method of  claim 1 , wherein the transmission limit is set to a legacy value for CE level 0 when the UE does not support CE. 
     
     
         6 . The method of  claim 1 , wherein the current CE level is CE level 0 and the transmission limit is set to a legacy value for CE level 0. 
     
     
         7 . The method of  claim 2 , wherein the transmission limit is a first transmission limit, the method further comprising:
 in response to ramping up to a higher CE level and resetting the value of the counter applying a second transmission limit for the higher CE level.   
     
     
         8 . The method of  claim 7 , wherein the first transmission limit and the second transmission limit are the same value. 
     
     
         9 . The method of  claim 7 , wherein the first transmission limit and the second transmission limit are different values. 
     
     
         10 . A user equipment (UE), comprising:
 an transceiver configured to transmit a random access preamble, wherein a power of the random access preamble is determined, in part, by a current coverage enhancement (CE) level;   processing circuitry communicatively coupled to the transceiver, the processing circuitry configured to:
 increment a value of a counter by one, wherein the value of the counter corresponds to the number of random access preambles previously transmitted by the UE; 
 compare the value of the counter, after incrementing its value, to a transmission limit, wherein the transmission limit indicates a maximum number of random access preamble transmission attempts for the current CE level; and 
 in response to the counter being equal to the transmission limit plus one, reset the value of the counter. 
   
     
     
         11 . The UE of  claim 10 , wherein in response to the counter being equal to the transmission limit plus one, the processing circuitry is further configured to ramp up to the next CE level. 
     
     
         12 . The UE of  claim 11 , wherein prior to ramping up to the higher CE level, the processing circuitry is further configured to:
 determine that the UE supports the higher CE level; and   determine that the higher CE level is supported by a cell, wherein the UE is transmitting the random access preamble from within a coverage area of the cell.   
     
     
         13 . The UE of  claim 10 , wherein in response to the value of the counter being less than the transmission limit, the processing circuitry is further configured to increase the power of the random access preamble. 
     
     
         14 . The UE of  claim 10 , wherein the transmission limit is set to a legacy value for CE level 0 when the UE does not support CE. 
     
     
         15 . The UE of  claim 10 , wherein the current CE level is CE level 0, the transmission limit is set to a legacy value for CE level 0. 
     
     
         16 . The UE of  claim 11 , wherein the transmission limit is a first transmission limit and, in response to ramping up to a higher CE level and resetting the value of the counter, the processing circuitry is further configured to apply a second transmission limit for the higher CE level. 
     
     
         17 . The UE of  claim 16 , wherein the first transmission limit and the second transmission limit are the same value. 
     
     
         18 . The UE of  claim 16 , wherein the first transmission limit and the second transmission limit are different values. 
     
     
         19 . A method in a network node for random access coverage enhancement (CE), the method comprising:
 broadcasting a transmission limit to a user equipment (UE) within a serving cell of the network node, wherein the transmission limit indicates a maximum number of random access preamble transmission attempts for one or more CE levels;   receiving a random access preamble transmission from the UE; and   transmitting a random access response message to the UE.   
     
     
         20 . The method of  claim 20 , further comprising communicating to the UE, an indication of a highest CE level supported by the serving cell. 
     
     
         21 . A network node, comprising:
 a transceiver, the transceiver configured to:
 broadcast a transmission limit to a user equipment (UE) within a serving cell of the network node, wherein the transmission limit indicates a maximum number of random access preamble transmission attempts for one or more CE levels; 
 receive a random access preamble transmission from the UE; and 
 transmit a random access response message to the UE. 
   
     
     
         22 . The network node of  claim 21 , where in the transceiver is further configured to: transmit, to the UE, an indication of a highest CE level supported by the serving cell. 
     
     
         23 . A non-transitory computer readable medium, comprising instructions which, when executed on at least one processor, causes the at least one processor to carry out the method according to  claim 1 . 
     
     
         24 . A non-transitory computer readable medium, comprising instructions which, when executed on at least one processor, causes the at least one processor to carry out the method according to  claim 19 .