Radio link failure detection procedures in long term evolution uplink and downlink and apparatus therefor

Abstract

A method and apparatus for detecting a radio link (RL) failure for uplink (UL) and downlink (DL) in a long term evolution (LTE) wireless communication system including at least one wireless transmit/receive unit (WTRU) and at least one evolved Node-B (eNodeB) are disclosed. A determination is made as to whether an RL has an in-synchronization status or an out-of-synchronization status. An RL failure is declared if an out-of-synchronization status is detected.

1 . A method, implemented by a wireless transmit/receive unit (WTRU), of determining a radio link (RL) synchronization status, the method comprising:
 determining a quality of a downlink (DL) common shared control physical channel communicated in a channel structure corresponding to a long-term evolution (LTE) compatible network;   comparing the quality to a predetermined threshold; and   determining the RL synchronization status, based at least in part, on the comparison.   
     
     
         2 . The method of  claim 1 , wherein the quality is based, at least in part, on a period of time. 
     
     
         3 . The method of  claim 1 , wherein the RL synchronization status is determined to be out-of-synchronization upon the comparison indicating an out-of-synchronization condition. 
     
     
         4 . The method of  claim 1  wherein the quality of the downlink (DL) common shared control physical channel is monitored on at least one of a continuous basis or a periodic basis. 
     
     
         5 . The method of  claim 3 , further comprising
 indicating the out-of-synchronization status to at least one logical layer in communication with a physical layer.   
     
     
         6 . The method of  claim 5  further comprising:
 transmitting a channel quality indicator (CQI) based on at least one of a measurement or estimation of at least one DL reference channel received by the WTRU. 
 
     
     
         7 . The method of  claim 5  further comprising:
 receiving a channel quality indicator (CQI) based on at least one of a measurement or estimation of at least one uplink (UL) reference channel. 
 
     
     
         8 . A wireless transmit/receive unit (WTRU configured to:
 determine a quality of downlink (DL) common shared control physical channel communicated in a channel structure corresponding to a long-term evolution (LTE) compatible network;   compare the quality to a predetermined threshold; and   determine an RL synchronization status, based at least in part, on the comparison.   
     
     
         9 . The WTRU of  claim 8  wherein the WTRU is configured to transmit a channel quality indicator (CQI) based on at least one of a measurement or estimation of at least one downlink (DL) reference channel received by the WTRU. 
     
     
         10 . The WTRU of  claim 8  wherein the RL synchronization status is determined to be out-of-synchronization upon the comparison indicating an out-of-synchronization condition. 
     
     
         11 . The WTRU of  claim 8  wherein the quality is monitored on at least one of a continuous or periodic basis. 
     
     
         12 . The WTRU of  claim 10  further configured to indicate that the out-of-synchronization status has been detected to a logical layer in communication with a physical layer. 
     
     
         13 . The WTRU of  claim 12 , wherein the WTRU is configured to transmit a channel quality indicator (CQI) based on at least one of a measurement or estimation of at least one DL reference channel received by the WTRU. 
     
     
         14 . The WTRU of  claim 12  wherein the WTRU is configured to receive a channel quality indicator (CQI) based on at least one of a measurement or estimation of at least one uplink (UL) reference channel. 
     
     
         15 . The WTRU of  claim 8  wherein the quality is based, at least in part, on a period of time.