LC-PDCCH Repetition Level Selection for MTC Devices

Abstract

There is provided mechanisms for configuring a UE. A base station is configured to configure the UE with a LC-PDCCH repetition level range selected from an ordered set of LC-PDCCH repetition level ranges using RRC signalling. The base station is configured to select a LC-PDCCH repetition level from the configured LC-PDCCH repetition level range for a transport block transmission to the UE. The UE is configured to receive the LC-PDCCH repetition level range as configuration information from the base station and using RRC signalling. The UE is configured to attempt decoding the LC-PDCCH according to at least one value in the configured LC-PDCCH repetition level range.

1 . A base station for configuring a user equipment, UE, the base station comprising a processor, the processor being configured to cause the base station to:
 configure the UE with a low complexity physical downlink control channel, LC-PDCCH, repetition level range selected from an ordered set of LC-PDCCH repetition level ranges using radio resource control, RRC, signaling; and   select a LC-PDCCH repetition level from the configured LC-PDCCH repetition level range for a transport block transmission to the UE.   
     
     
         2 . The base station according to  claim 1 , wherein adjacent LC-PDCCH repetition level ranges in the set of LC-PDCCH repetition level ranges are partly overlapping. 
     
     
         3 . The base station according to  claim 1 , the processor further being configured to cause the base station to:
 configure the UE in frequency domain by instructing the UE to operate on two, four, or six pairs of physical recourse blocks, PRBs, within a group of 6 PRBs in a subframe of the LC-PDCCH.   
     
     
         4 . The base station according to  claim 3 , wherein location of the PRBs within the group is indicated in the configuration by at most 2 bits. 
     
     
         5 . The base station according to  claim 3 , wherein the base station configures the LC-PDCCH repetition level range and configures the UE in frequency domain either separately and independently or jointly. 
     
     
         6 . The base station according to  claim 1 , the processor further being configured to cause the base station to:
 obtain an indication of current channel conditions, wherein the current channel conditions correspond to an LC-PDCCH repetition threshold level; and   select the LC-PDCCH repetition level based on the indication of current channel conditions such that the LC-PDCCH repetition level is higher than the LC-PDCCH repetition threshold level.   
     
     
         7 . The base station according to  claim 1 , the processor further being configured to cause the base station to:
 select the LC-PDCCH repetition level such that the LC-PDCCH repetition level involves a first period comprising a first number of repetitions and a second period comprising a second number of repetitions, and wherein the repetitions in the second period are more densely placed than in the first period.   
     
     
         8 . A user equipment, UE, for obtaining configuration, the UE comprising a processor configured to cause the UE to:
 receive configuration information for a low complexity physical downlink control channel, LC-PDCCH, repetition level range selected from an ordered set of LC-PDCCH repetition level ranges using radio resource control, RRC, signaling from a base station; and   attempt decoding the LC-PDCCH according to at least one value in the configured LC-PDCCH repetition level range.   
     
     
         9 . The UE according to  claim 8 , the processor further being configured to cause the UE to, when the decoding attempt was unsuccessful and there is at least one higher value in the configured LC-PDCCH repetition level range:
 attempt decoding the LC-PDCCH according to at least one of said at least one higher value in the LC-PDCCH repetition level range.   
     
     
         10 . The UE according to  claim 8 , the processor further being configured to cause the UE to:
 receive an indication indicating the at least one value of the LC-PDCCH repetition level range.   
     
     
         11 . The UE according to  claim 8 , wherein adjacent LC-PDCCH repetition levels in the set of LC-PDCCH repetition level ranges are partly overlapping. 
     
     
         12 . The UE according to  claim 8 , the processor further being configured to cause the UE to:
 receive instructions from the base station for configuring the UE in frequency domain by instructing the UE to operate on two, four, or six pairs of physical recourse blocks, PRBs, within a group of 6 PRBs in a subframe of the LC-PDCCH; and   attempt decoding two, four, or six pairs of PRBs within the group of 6 PRBs in a subframe of the LC-PDCCH according to the instructions.   
     
     
         13 . The UE according to  claim 12 , wherein location of the PRBs within the group is indicated in the instructions by at most 2 bits. 
     
     
         14 . The UE according to  claim 8 , wherein the LC-PDCCH repetition level involves a first period comprising a first number of repetitions and a second period comprising a second number of repetitions, and wherein the repetitions in the second period are more densely placed than in the first period. 
     
     
         15 . A method for configuring a user equipment, UE, the method being performed by a base station, the method comprising:
 configuring the UE with a low complexity physical downlink control channel, LC-PDCCH, repetition level range selected from an ordered set of LC-PDCCH repetition level ranges using radio resource control, RRC, signaling; and   selecting a LC-PDCCH repetition level from the configured LC-PDCCH repetition level range for a transport block transmission to the UE.   
     
     
         16 . The method according to  claim 15 , further comprising:
 configuring the UE in frequency domain by instructing the UE to operate on two, four, or six pairs of physical recourse blocks, PRBs, within a group of 6 PRBs in a subframe of the LC-PDCCH.   
     
     
         17 . The method according to  claim 15 , further comprising:
 obtaining an indication of current channel conditions, wherein the current channel conditions correspond to an LC-PDCCH repetition threshold level; and   selecting the LC-PDCCH repetition level based on the indication of current channel conditions such that the LC-PDCCH repetition level is higher than the LC-PDCCH repetition threshold level.   
     
     
         18 . The method according to  claim 15 , further comprising:
 selecting the LC-PDCCH repetition level such that the LC-PDCCH repetition level involves a first period comprising a first number of repetitions and a second period comprising a second number of repetitions, and wherein the repetitions in the second period are more densely placed than in the first period.   
     
     
         19 . A method for obtaining configuration of a user equipment, UE, the method being performed by the UE, the method comprising:
 receiving configuration information for a low complexity physical downlink control channel, LC-PDCCH, repetition level range selected from an ordered set of LC-PDCCH repetition level ranges using radio resource control, RRC, signaling from a base station; and   attempting decoding the LC-PDCCH according to at least one value in the configured LC-PDCCH repetition level range.   
     
     
         20 . The method according to  claim 19 , further comprising, when the decoding attempt was unsuccessful and there is at least one higher value in the configured LC-PDCCH repetition level range:
 attempting decoding the LC-PDCCH according to at least one of said at least one higher value in the LC-PDCCH repetition level range.   
     
     
         21 . The method according to  claim 19 , further comprising:
 receiving an indication indicating the at least one value of the LC-PDCCH repetition level range.   
     
     
         22 . The method according to  claim 19 , further comprising:
 receiving instructions from the base station for configuring the UE in frequency domain by instructing the UE to operate on two, four, or six pairs of physical recourse blocks, PRBs, within a group of 6 PRBs in a subframe of the LC-PDCCH; and   attempting decoding two, four, or six pairs of PRBs within the group of 6 PRBs in a subframe of the LC-PDCCH according to the instructions.   
     
     
         23 . A non-transitory computer readable medium operative to store a computer program for configuring a user equipment, UE, the computer program comprising computer code which, when run on a processor of a base station, causes the base station to:
 configure the UE with a low complexity physical downlink control channel, LC-PDCCH, repetition level range selected from an ordered set of LC-PDCCH repetition level ranges using radio resource control, RRC, signaling; and   select a LC-PDCCH repetition level from the configured LC-PDCCH repetition level range for a transport block transmission to the UE.   
     
     
         24 . A non-transitory computer readable medium operative to store a computer program for obtaining configuration of a user equipment, UE, the computer program comprising computer code which, when run on a processor of the UE, causes the UE to:
 receive configuration information for a low complexity physical downlink control channel, LC-PDCCH, repetition level range selected from an ordered set of LC-PDCCH repetition level ranges using radio resource control, RRC, signaling from a base station; and   attempt decoding the LC-PDCCH according to at least one value in the configured LC-PDCCH repetition level range.