Measurement Procedures for Operation in Unlicensed Spectrum

Abstract

A novel way for transmitting physical signals by a transmitter node ( 20, 40 ) based on the LBT principle, and informing a receiver node ( 30, 50 ) in cases where the transmission of the physical signals has been deferred or does not occur in a certain time resource, is presented. A transmitter node ( 20, 40 ) listens to a wireless radio channel during a first time resource. If there is no activity, or if the activity is below a threshold, the transmitter node ( 20, 40 ), in a second time resource, transmits an indicator indicating that one or more physical signals are also transmitted in the second time resource. A receiver node ( 30, 50 ) detects if an indicator is present in the time resource. If the receiver node ( 30, 50 ) detects the indicator, the receiver node ( 30, 50 ) may also receive and use one or more reference signals in the current time resource for doing one or more tasks.

1 - 40 . (canceled) 
     
     
         41 . A method, implemented in a transmitter node configured to communicate with a receiver node via a wireless radio channel, the method comprising:
 determining whether the wireless radio channel between the transmitter node and the receiver node is idle during a first time resource; and   if the wireless radio channel is idle during the first time resource, subsequently transmitting a first indicator and one or more first references signals from the transmitter node in a second time resource, the first indicator for alerting the receiver node to the presence of the one or more first reference signals in the second time resource;   wherein the second time resource occurs after the first time resource.   
     
     
         42 . The method of  claim 41 , further comprising transmitting one or more additional reference signals in the second time resource to compensate for the inability of the transmitter node to transmit reference signals in a previous time resource occurring before the second time resource. 
     
     
         43 . The method of  claim 42 , wherein the previous time resource occurs before the first time resource. 
     
     
         44 . The method of  claim 41 , further comprising transmitting one or more additional reference signals in the second time resource to compensate for degradations in the wireless radio channel between the transmitter node and the receiver node. 
     
     
         45 . The method of  claim 41 , further comprising refraining from transmitting in the second time resource if the wireless radio channel is not idle. 
     
     
         46 . The method of  claim 41 , wherein the transmitter node is configured to communicate with the receiver node using unlicensed spectrum. 
     
     
         47 . The method of  claim 41 , wherein determining whether the wireless radio channel between the transmitter node and the receiver node is idle during the first time resource comprises determining whether the wireless radio channel between the transmitter node and the receiver node is idle during the first time resource by using at least one of:
 a Carrier Sense Multiple Access (CSMA) protocol; and   a Listen Before Talk (LBT) procedure.   
     
     
         48 . The method of  claim 41 , further comprising sending an indicator control signal to the receiver node, the indicator control signal informing the receiver node that only time resources containing a reference signal indicator also contain reference signals. 
     
     
         49 . The method of  claim 41 , further comprising transmitting, if the wireless radio channel is idle during the first time resource, a second indicator and one or more second reference signals from the transmitter node in the second time resource, the second indicator for alerting the receiver node to the presence of the one or more second reference signals in the second time resource, wherein the one or more second reference signals differ from the one or more first reference signals. 
     
     
         50 . The method of  claim 41 , further comprising receiving capability information from the receiver node, the capability information informing the transmitter node of a capability of the receiver node to detect and interpret the first indicator. 
     
     
         51 . A transmitter node configured to communicate with a receiver node via a wireless radio channel, the transmitter node comprising:
 an activity determination circuit configured to determine whether the wireless radio channel between the transmitter node and the receiver node is idle during a first time resource; and   a transmission circuit configured to subsequently transmit a first indicator and one or more first reference signals in a second time resource if the wireless radio channel is idle during the first time resource, the first indicator for alerting the receiver node to the presence of the one or more first reference signals in the second time resource, wherein the second time resource occurs after the first time resource.   
     
     
         52 . The transmitter node of  claim 51 , wherein the transmission circuit is further configured to transmit one or more additional reference signals in the second time resource to compensate for the inability of the transmission circuit to transmit reference signals in a previous time resource. 
     
     
         53 . The transmitter node of  claim 52 , wherein the previous time resource occurs before the first time resource. 
     
     
         54 . The transmitter node of  claim 51 , wherein the transmission circuit is further configured to transmit one or more additional reference signals in the second time resource to compensate for degradations in the wireless radio channel between the transmitter node and the receiver node. 
     
     
         55 . The transmitter node of  claim 51 , wherein the transmission circuit is further configured to refrain from transmitting in the second time resource if the wireless radio channel is not idle. 
     
     
         56 . The transmitter node of  claim 51 , wherein the transmitter node is configured to communicate with the receiver node using unlicensed spectrum. 
     
     
         57 . The transmitter node of  claim 51 , wherein the activity determination circuit is configured to determine whether the wireless radio channel between the transmitter node and the receiver node is idle during a first time resource by using at least one of:
 a Carrier Sense Multiple Access (CSMA) protocol; and   a Listen Before Talk (LBT) procedure.   
     
     
         58 . The transmitter node of  claim 51 , wherein the transmission circuit is further configured to send an indicator control signal to the receiver node, the indicator control signal informing the receiver node that only time resources containing a reference signal indicator also contain reference signals. 
     
     
         59 . The transmitter node of  claim 51 , wherein the transmission circuit is further configured to transmit, if the wireless radio channel is idle during the first time resource, a second indicator and one or more second reference signals from the transmitter node in the second time resource, the second indicator alerting the receiver node to the presence of the one or more second reference signals in the second time resource, wherein the one or more second reference signals differ from the one or more first reference signals. 
     
     
         60 . The transmitter node of  claim 51 , further comprising a reception circuit configured to receive capability information from the receiver node, the capability information informing the transmitter node of a capability of the receiver node to detect and interpret the first indicator. 
     
     
         61 . A method, implemented in a receiver node configured to communicate with a transmitter node via a wireless radio channel, the method comprising:
 determining whether a first indicator is present in a first time resource received from the transmitter node via the wireless radio channel; and   if the first indicator is present in the first time resource, using one or more first reference signals present in the first time resource to execute one or more tasks.   
     
     
         62 . The method of  claim 61 , further comprising sending, before the reception of the first time resource, a request from the receiver node to the transmitter node for one or more compensated reference signal transmissions. 
     
     
         63 . The method of  claim 61 , further comprising:
 receiving one or more compensated reference signals present in the first time resource; and   processing the one or more compensated reference signals if the first indicator is present in the first time resource.   
     
     
         64 . The method of  claim 61 , wherein the first indicator indicates the wireless radio channel between the transmitter node and the receiver node is idle during a previous time resource occurring before the first time resource. 
     
     
         65 . The method of  claim 61 , further comprising, if the first indicator is not present in the first time resource, refraining from using signals present in the first time resource for the one or more tasks. 
     
     
         66 . The method of  claim 61 , further comprising receiving an indicator control signal from the transmitter node, the indicator control signal informing the receiver node that only time resources containing a reference signal indicator also contain reference signals. 
     
     
         67 . The method of  claim 61 , further comprising sending capability information to the transmitter node, the capability information informing the transmitter node of a capability of the receiver node to detect and interpret the first indicator. 
     
     
         68 . The method of  claim 61 , further comprising:
 determining whether a second indicator is present in the first time resource; and   if the second indicator is present in the first time resource, processing one or more second reference signals present in the first time resource, wherein the one or more second reference signals differ from the one or more first reference signals.   
     
     
         69 . The method of  claim 61 , wherein the one or more tasks comprise:
 performing one or more radio measurements;   processing data;   saving power by turning on or off one or more components in the receiver node depending on whether the first or second indicator is received; and   sending a request to the transmitter node for at least one of additional reference signals and a more dense distribution of reference signals.   
     
     
         70 . A receiver node configured to communicate with a transmitter node via a wireless radio channel, the receiver node comprising:
 a processing circuit configured to:
 determine whether a first indicator is present in a first time resource received from the transmitter node via the wireless radio channel; and 
 if the first indicator is present in the first time resource, use one or more first reference signals present in the first time resource to execute one or more tasks. 
   
     
     
         71 . The receiver node of  claim 70 , further comprising a transmission circuit configured to send, before the receiver node receives the first time resource, a request to the transmitter node for one or more compensated reference signal transmissions. 
     
     
         72 . The receiver node of  claim 70 , further comprising a reception circuit configured to receive one or more compensated reference signals present in the first time resource, wherein the processing circuit is further configured to process the one or more compensated reference signals. 
     
     
         73 . The receiver node of  claim 70 , wherein the first indicator indicates the wireless radio channel between the transmitter node and the receiver node is idle during a previous time resource occurring before the first time resource. 
     
     
         74 . The receiver node of  claim 70 , wherein the processing circuit is further configured to, if the first indicator is not present in the first time resource, refrain from using signals present in the first time resource for the one or more tasks. 
     
     
         75 . The receiver node of  claim 70 , further comprising a reception circuit configured to receive an indicator control signal from the transmitter node, the indicator control signal informing the receiver node that only time resources containing a reference signal indicator also contain reference signals. 
     
     
         76 . The receiver node of  claim 70 , further comprising a transmission circuit configured to send capability information to the transmitter node, the capability information informing the transmitter node of a capability of the receiver to detect and interpret the first indicator. 
     
     
         77 . The receiver node of  claim 70 , wherein the processing circuit is further configured to:
 determine whether a second indicator is present in the first time resource; and   if the second indicator is present in the first time resource, process one or more second reference signals present in the first time resource, wherein the one or more second reference signals differ from the one or more first reference signals.   
     
     
         78 . The receiver node of  claim 70 , wherein the one or more tasks comprise:
 a performance of one or more radio measurements;   a processing of data;   a saving of power by turning on or off one or more components in the receiver node depending on whether the first or second indicator is received; and   a sending of a request to the transmitter node for at least one of additional reference signals and a more dense distribution of reference signals.   
     
     
         79 . A computer program product stored in a non-transitory computer readable medium for controlling a transmitter node, the computer program product comprising software instructions which, when run on the transmitter node, causes the transmitter node to:
 determine whether a wireless radio channel between the transmitter node and a receiver node is idle during a first time resource; and   subsequently transmit an indicator from the transmitter node if the radio channel is idle during the first time resource, the indicator for alerting the receiver node to the presence of one or more reference signals in the second time resource, wherein the second time resource occurs after the first time resource.   
     
     
         80 . A computer program product stored in a non-transitory computer readable medium for controlling a receiver node, the computer program product comprising software instructions which, when run on the receiver node, causes the receiver node to:
 determine whether an indicator is present in a first time resource received from a transmitter node via a wireless radio channel; and   if the indicator is present in the first time resource, use one or more reference signals present in the first time resource to execute one or more tasks.