Method and mobile terminal for performing random access

Abstract

A mobile terminal performs a random access procedure with a network that includes transmitting to the network a random access preamble directly allocated to the mobile terminal by the network and receiving a random access response from the network in response to transmission of the random access preamble. The terminal performs a discontinuous reception (DRX) operation that controls how the mobile terminal monitors a physical downlink control channel (PDCCH). The DRX operation employs an active time in which the mobile terminal monitors the PDCCH, and the active time includes a time while: (i) an on-duration timer or a DRX Inactivity timer or a DRX retransmission timer or a contention resolution timer is operating, (ii) a scheduling request procedure is pending, (iii) an uplink grant for a retransmission can occur, or (iv) the PDCCH indicating a new transmission addressed to a Cell-Radio Network Temporary Identifier (C-RNTI) of the mobile terminal has not yet been received after successful reception of the random access response.

1 . A mobile terminal configured to perform a random access procedure with a network, comprising:
 a transmitter to transmit to the network a random access preamble directly allocated to the mobile terminal by the network; and   a receiver to receive a random access response from the network in response to transmission of the random access preamble;   processing circuitry in communication with the transmitter and the receiver, the processing circuitry being configured to perform a discontinuous reception (DRX) operation that controls how the mobile terminal monitors a physical downlink control channel (PDCCH),   wherein the DRX operation employs an active time in which the mobile terminal monitors the PDCCH, and   wherein the active time includes a time while:
 (i) an on-duration timer or a DRX Inactivity timer or a DRX retransmission timer or a contention resolution timer is operating, 
 (ii) a scheduling request procedure is pending, 
 (iii) an uplink grant for a retransmission can occur, or 
 (iv) the PDCCH indicating a new transmission addressed to a Cell-Radio Network Temporary Identifier (C-RNTI) of the mobile terminal has not yet been received after successful reception of the random access response. 
   
     
     
         2 . The mobile terminal in  claim 1 , wherein for a configured DRX cycle, the processing circuitry is configured to start the on-duration timer when the PDCCH is monitored by the mobile terminal. 
     
     
         3 . The mobile terminal in  claim 1 , wherein for a configured DRX cycle for a sub-frame of the PDCCH monitored by the mobile terminal, the processing circuitry is configured, in response to determining that an Hybrid Automatic Repeat Request (HARD) round trip time (RTT) timer expires in the sub-frame and data associated with the sub-frame was not successfully decoded, start the DRX retransmission timer. 
     
     
         4 . The mobile terminal in  claim 3 , wherein during the active time for the sub-frame of the PDCCH monitored by the mobile terminal, the processing circuitry is configured, in response to the PDCCH indicating a new downlink transmission or a new uplink transmission, to start or restart the DRX Inactivity Timer. 
     
     
         5 . The mobile terminal in  claim 1 , wherein the random access preamble is a dedicated preamble and is explicitly signaled from the network. 
     
     
         6 . The mobile terminal in  claim 1 , wherein the random access preamble is part of a handover message. 
     
     
         7 . The mobile terminal in  claim 1 , wherein the random access response includes at least one of an uplink grant for uplink radio resources, a C-RNTI, and a value for time synchronization adjustment. 
     
     
         8 . The mobile terminal in  claim 1 , wherein the mobile terminal is configured to wake up from an power saving state at a start of the DRX active time, and wherein the mobile terminal need not monitor the PDCCH when the DRX active time expires. 
     
     
         9 . The mobile terminal in  claim 1 , wherein the DRX active time denotes a time from after receiving the random access response to a time when an indication of radio resource allocation information for an uplink data transmission is received. 
     
     
         10 . The mobile terminal in  claim 1 , wherein the DRX active time denotes a time from after receiving the random access response to a time when scheduling information for an uplink data transmission is received. 
     
     
         11 . A method for a mobile terminal to perform a random access procedure with a network comprising:
 transmitting to the network a random access preamble directly allocated to the mobile terminal by the network;   receiving a random access response from the network in response to transmission of the random access preamble;   performing a discontinuous reception (DRX) operation that controls how the mobile terminal monitors a physical downlink control channel (PDCCH),   wherein the DRX operation employs an active time in which the mobile terminal monitors the PDCCH, and   wherein the active time includes a time while:
 (i) an on-duration timer or a DRX Inactivity timer or a DRX retransmission timer or a contention resolution timer is operating, 
 (ii) a scheduling request procedure is pending, 
 (iii) an uplink grant for a retransmission can occur, or 
 (iv) the PDCCH indicating a new transmission addressed to a Cell-Radio Network Temporary Identifier (C-RNTI) of the mobile terminal has not yet been received after successful reception of the random access response. 
   
     
     
         12 . The method in  claim 11 , wherein for a configured DRX cycle, the method further comprises starting the on-duration timer when the PDCCH is monitored by the mobile terminal. 
     
     
         13 . The method in  claim 11 , wherein for a configured DRX cycle for a sub-frame of the PDCCH monitored by the mobile terminal, the method further comprises, in response to determining that an Hybrid Automatic Repeat Request (HARD) round trip time (RTT) timer expires in the sub-frame and data associated with the sub-frame was not successfully decoded, start the DRX retransmission timer. 
     
     
         14 . The method in  claim 11 , wherein during the active time for a sub-frame of the PDCCH monitored by the mobile terminal, the method further comprises, in response to the PDCCH indicating a new downlink transmission or a new uplink transmission, starting or restarting the DRX Inactivity Timer. 
     
     
         15 . The method in  claim 11 , wherein the random access preamble is a dedicated preamble and is explicitly signaled from the network. 
     
     
         16 . The method in  claim 11 , wherein the random access preamble is part of a handover message. 
     
     
         17 . The method in  claim 11 , wherein the random access response includes at least one of an uplink grant for uplink radio resources, a C-RNTI, and a value for time synchronization adjustment. 
     
     
         18 . The method in  claim 11 , wherein the mobile terminal wakes up from an power saving state at a start of the DRX active time, and wherein the mobile terminal need not monitor the PDCCH when the DRX active time expires. 
     
     
         19 . The method in  claim 11 , wherein the DRX active time denotes a time from after receiving the random access response to a time when an indication of radio resource allocation information for an uplink data transmission is received. 
     
     
         20 . The method in  claim 11 , wherein the DRX active time denotes a time from after receiving the random access response to a time when scheduling information for an uplink data transmission is received.