Radio link monitoring in a wireless communication device

Abstract

Methods and apparatus' of determining radio link quality are disclosed. According to various implementations, a user equipment detects an out-of-synchronization condition corresponding to a first control channel, and monitors a second control channel in response to the detecting the out-of synchronization condition.

1 . A method in user equipment, the method comprising:
 detecting an out-of-synchronization condition corresponding to a first control channel;   in response to the detecting the out-of synchronization condition:
 monitoring of a second control channel, and 
 transmitting a distress signal to the network; and 
   receiving on the second control channel, in response to the transmitting, a response from the network to the reception of the distress signal, and based on the response from the network, at least one of:   scheduling communication on the second control channel, or reconfiguring the first control channel,   wherein the first control channel is an Enhanced Physical Downlink Control Channel and the second control channel is a Physical Downlink Control Channel.   
     
     
         2 . The method of  claim 1 , wherein transmitting the distress signal comprises transmitting a random access preamble to the network, the random access preamble chosen from a subset of random access preambles supported by a user equipment,
 and the response from the network having been transmitted on downlink control information on a user equipment-specific search space on the second control channel.   
     
     
         3 . The method of  claim 2 , wherein the random access preamble is a pre-assigned preamble to indicate an out-of-synchronization condition. 
     
     
         4 . The method of  claim 1 , wherein monitoring of the second control channel further comprises at least one of:
 monitoring a common search space on the second control channel; or   initiating monitoring of a user specific search space on the second control channel.   
     
     
         5 . The method of  claim 1 , wherein the monitoring of the second control channel comprises resuming monitoring of the second control channel in response to the detecting the out-of synchronization condition. 
     
     
         6 . The method of  claim 5 , wherein the out-of synchronization condition is an onset of an out-of-synchronization condition corresponding to a first threshold, the method further comprising:
 monitoring, in response to the detection of the onset of the out-of-synchronization condition, both the first control channel and the second control channel.   
     
     
         7 . The method of  claim 1 , wherein at least one of:
 the second control channel is received on a carrier different from the carrier on which the first control channel was received; or   the receiving, in response to the transmitting includes receiving a message to stop monitoring the first control channel and to initiate monitoring the second control channel.   
     
     
         8 . The method of  claim 1 , further comprising one of:
 receiving a uplink indicator channel configuration from the network, the uplink indicator channel used for transmitting a lack of reliability of the first control channel or out-of-synchronization condition; or
 receiving a periodic assignment for the uplink indicator channel, prior to the detecting of an out-of-synchronization condition corresponding to a first control channel. 
   
     
     
         9 . The method of  claim 1 , wherein at least one of:
 the monitoring the second control channel comprises monitoring the second control channel for a contention grant,   the method further comprising transmitting by the user equipment channel quality information corresponding to the first control channel carrier using the contention grant, the transmission including an identity of the user equipment; or   the monitoring the second control channel comprises monitoring the second control channel for a contention grant in response to the detecting the out-of-synchronization condition on the first control channel.   
     
     
         10 . The method of  claim 1 , wherein at least one of:
 the distress signal is transmitted as an alert using a periodic PUSCH channel; further comprising transmitting, on the first control channel, channel quality information; or   the method further comprising masking a cyclic redundancy check associated with a payload of a transmission on the PUSCH channel by one or more bits to indicate that the channel quality information included in the transmission is the channel quality corresponding to the first control channel.   
     
     
         11 . The method of  claim 1 , wherein at least one of:
 the response from the network provides at least an uplink grant to the user equipment; or   the method further comprising transmitting radio condition information to the network relating to the first control channel in response to receiving the response from the network.   
     
     
         12 . A user equipment configured to perform a method, the method comprising:
 detecting an out-of-synchronization condition corresponding to a first control channel;   in response to the detecting the out-of synchronization condition:
 monitoring of a second control channel, and 
 transmitting a distress signal to the network; and 
   receiving on the second control channel, in response to the transmitting, a response from the network to the reception of the distress signal, and, based on the response from the network, at least one of:   scheduling communication on the second control channel, or reconfiguring the first control channel,   wherein the first control channel is an Enhanced Physical Downlink Control Channel and the second control channel is a Physical Downlink Control Channel.   
     
     
         13 . The user equipment of  claim 12 , wherein transmitting the distress signal comprises transmitting a random access preamble to the network, the random access preamble chosen from a subset of random access preambles supported by a user equipment,
 and the response from the network having been transmitted on downlink control information on a user equipment-specific search space on the second control channel.   
     
     
         14 . The user equipment of  claim 13 , wherein the random access preamble is a pre-assigned preamble to indicate an out-of-synchronization condition. 
     
     
         15 . The user equipment of  claim 12 , wherein monitoring of the second control channel further comprises at least one of:
 monitoring a common search space on the second control channel; or   initiating monitoring of a user specific search space on the second control channel.   
     
     
         16 . The user equipment of  claim 12 , wherein the monitoring of the second control channel comprises resuming monitoring of the second control channel in response to the detecting the out-of synchronization condition. 
     
     
         17 . The user equipment of  claim 16 , wherein the out-of synchronization condition is an onset of an out-of-synchronization condition corresponding to a first threshold, the method further comprising:
 monitoring, in response to the detection of the onset of the out-of-synchronization condition, both the first control channel and the second control channel.   
     
     
         18 . The user equipment of  claim 12 , wherein at least one of:
 the second control channel is received on a carrier different from the carrier on which the first control channel was received; or   the receiving, in response to the transmitting includes receiving a message to stop monitoring the first control channel and to initiate monitoring the second control channel.   
     
     
         19 . The user equipment of  claim 12 , wherein at least one of:
 the monitoring the second control channel comprises monitoring the second control channel for a contention grant,   the method further comprising transmitting by the user equipment channel quality information corresponding to the first control channel carrier using the contention grant, the transmission including an identity of the user equipment; or   the monitoring the second control channel comprises monitoring the second control channel for a contention grant in response to the detecting the out-of-synchronization condition on the first control channel.   
     
     
         20 . The user equipment of  claim 12 , wherein at least one of:
 the distress signal is transmitted as an alert using a periodic PUSCH channel; further comprising transmitting, on the first control channel, channel quality information; or   the method further comprising masking a cyclic redundancy check associated with a payload of a transmission on the PUSCH channel by one or more bits to indicate that the channel quality information included in the transmission is the channel quality corresponding to the first control channel.