Method of access and link adaptation for coverage enhanced wireless transmissions

Abstract

Coverage enhancement of channels in a wireless communication system such as Long Term Evolution (LTE) and LTE-Advanced (LTE-A). Coverage enhancement may include repetition of a channel in the time and/or frequency domain, power boosting of the channel, and reference signal improvement for better channel estimation accuracy. Link adaptation techniques are described, where the link adaptation is dependent on a coverage enhancement (CE) or repetition level. An example method for link adaptation in a Wireless Transmit/Receive Unit (WTRU) in coverage enhancement (CE) mode includes determining the number of repetitions for an uplink channel, deriving the transmission power for the uplink channel based on the number of repetitions, and transmitting the channel with the determined number of repetitions at the transmission power level. Link adaptation based on CE level or repetition level is described for uplink and downlink channels including data, control, access, and broadcast channels.

1 . A method performed by an eNodeB having an associated a physical cell ID (PCID), the method comprising:
 allocating a frequency resource for transmission of a coverage-enhanced system information block (CE-SIB), wherein the frequency resource is allocated based at least in part on the PCID; and   transmitting the CE-SIB from the eNodeB using the allocated frequency resource.   
     
     
         2 . The method of  claim 1 , wherein the allocation of the frequency resource is further based at least in part based on a system bandwidth. 
     
     
         3 . The method of  claim 1 , further comprising allocating a time location for the CE-SIB based at least in part on the PCID, wherein the CE-SIB is transmitted using the allocated time location. 
     
     
         4 . The method of  claim 1 , wherein the allocation of the frequency resource is further based at least in part on a subframe number. 
     
     
         5 . The method of  claim 1 , wherein the frequency resource allocation for the CE-SIB is not transmitted in a physical downlink control channel (PDCCH). 
     
     
         6 . The method of  claim 1 , further comprising transmitting a master information block (MIB) from the eNodeB, wherein the MIB indicates a periodicity of the CE-SIB, and wherein the CE-SIB is transmitted with the periodicity indicated in the MIB. 
     
     
         7 . The method of  claim 1 , further comprising transmitting a master information block (MIB) from the eNodeB, wherein the MIB indicates a modulation and coding scheme (MCS) level of the CE-SIB, and wherein the MCS level is a function of the transport block size (TBS) of the CE-SIB. 
     
     
         8 . A method performed at a wireless transmit and receive unit (WTRU), the method comprising:
 receiving, from an eNodeB, a physical cell ID (PCID) associated with the eNodeB,   allocating a frequency resource for receipt of a coverage-enhanced system information block (CE-SIB), wherein the frequency resource is allocated based at least in part on the PCID; and   receiving the CE-SIB from the eNodeB in the allocated frequency resource.   
     
     
         9 . The method of  claim 8 , wherein the allocation of the frequency resource is further based at least in part based on a system bandwidth. 
     
     
         10 . The method of  claim 8 , further comprising allocating a time location for the CE-SIB based at least in part on the PCID, wherein the CE-SIB is received in the allocated time location. 
     
     
         11 . The method of  claim 8 , wherein the allocation of the frequency resource is further based at least in part on a subframe number. 
     
     
         12 . The method of  claim 8 , further comprising receiving a master information block (MIB) from the eNodeB, wherein the MIB indicates a periodicity of the CE-SIB, and wherein the CE-SIB is received with the periodicity indicated in the MIB. 
     
     
         13 . The method of  claim 8 , further comprising receiving a master information block (MIB) from the eNodeB, wherein the MIB indicates a modulation and coding scheme (MCS) level of the CE-SIB, and wherein the MCS level is a function of the transport block size (TBS) of the CE-SIB. 
     
     
         14 . A method performed at a wireless transmit and receive unit (WTRU), the method comprising:
 for a current coverage enhancement (CE) level, determining a maximum number of attempts for physical random access channel (PRACH) preamble transmission;   repeatedly transmitting the PRACH preamble until a corresponding random access response (RAR) is received; and   in response to transmission of the PRACH preamble for the determined maximum number of attempts, increasing the CE level to a next CE level.   
     
     
         15 . The method of  claim 14 , wherein the next CE level is associated with a second a maximum number of attempts.