Method and Apparatus For Signal Quality Determination in a Communication Network

Abstract

One aspect of the present invention is method for signal quality measurement that provides significant improvements in accuracy, at least in certain scenarios where conventional approaches to such measurements are vulnerable to inaccuracies. Non-limiting example scenarios include instances where a communication network uses downlink carriers in neighboring cells with overlapping frequencies but with different bandwidths and/or center frequencies. In such cases, there may be uneven interference across the carrier bandwidth, e.g., arising from neighboring carriers operating at different center frequencies and/or at different bandwidths. Thus, making the signal quality measurement for a given carrier depend on a combination of measurements taken at different frequency regions of the carrier provides a clearer, more accurate picture of the interference or loading conditions bearing on that carrier.

What is claimed is: 
     
         1 . A method of operation in a wireless communication device configured for operation in a communication network comprising:
 determining a signal quality of a downlink carrier of a cell in the communication network according to a first type of signal quality determination that includes obtaining multiple signal quality measurements from first and second frequency regions of the downlink carrier, and determining the signal quality of the downlink carrier as a function of the multiple signal quality measurements; and   performing at least one radio operation task using the determined signal quality.   
     
     
         2 . The method of  claim 1 , further comprising obtaining the signal quality measurements from the first frequency region at a different time from which the signal quality measurements are obtained from the second frequency region, such that the signal quality measurements for the first and second frequency regions are taken from disjoint frequency regions and at disjoint times. 
     
     
         3 . The method of  claim 1 , wherein the step of determining the signal quality of the downlink carrier according to the first type of signal quality determination is a selective step, and wherein the method further includes deciding whether to determine the signal quality of the downlink carrier using the first type of signal quality determination or a different, second type of signal quality determination. 
     
     
         4 . The method of  claim 3 , wherein the first type of signal quality determination comprises measuring signal quality in the first and second frequency regions as positioned on respective sides of a center frequency of the downlink carrier and the second type of signal quality determination comprises measuring signal quality in a single frequency region on the center frequency of the downlink carrier. 
     
     
         5 . The method of  claim 3 , wherein deciding whether to determine the signal quality of the downlink carrier using the first type of signal quality determination or the second type of signal quality determination comprises making said decision responsive to a control indicator received from the communication network. 
     
     
         6 . The method of  claim 3 , further comprising deciding to use the first type of signal quality determination instead of the second type of signal quality determination when one or more of the following conditions applies:
 network configuration information received or determined by the wireless communication device indicates that two or more cells in the network that are of interest with respect to signal quality determination have overlapping downlink carrier frequencies but have different bandwidths and/or different center frequencies; and   measurement requirements information received or determined by the wireless communication device indicates that the first type of signal quality determination is preferred.   
     
     
         7 . A wireless communication device configured for operation in a communication network comprising:
 a transceiver configured to receive a downlink carrier of a cell in the communication network; and   one or more processing circuits operatively associated with the transceiver and configured to:
 determine a signal quality of a downlink carrier of a cell in the communication network according to a first type of signal quality determination, wherein the one or more processing circuits are configured to obtain multiple signal quality measurements from first and second frequency regions of the downlink carrier, and determine the signal quality of the downlink carrier as a function of the multiple signal quality measurements; and 
 perform at least one radio operation task using the determined signal quality. 
   
     
     
         8 . The wireless communication device of  claim 7 , wherein the one or more processing circuits are configured to obtain the signal quality measurements from the first frequency region at a different time than used to obtain the signal quality measurements from the second frequency region, such that the signal quality measurements for the first and second frequency regions are taken at disjoint frequency regions and at disjoint times. 
     
     
         9 . The wireless communication device of  claim 7 , wherein the one or more processing circuits are further configured to determine the signal quality of the downlink carrier according to the first type of signal quality determination as a selective step, based on being configured to decide whether to determine the signal quality of the downlink carrier using the first type of signal quality determination or using a different, second type of signal quality determination. 
     
     
         10 . The wireless communication device of  claim 9 , wherein the one or more processing circuits are configured to perform the first type of signal quality determination by measuring signal quality in the first and second frequency regions as positioned on respective sides of a center frequency of the downlink carrier and the second type of signal quality determination comprises measuring signal quality in a single frequency region at the center frequency of the downlink carrier. 
     
     
         11 . The wireless communication device of  claim 9 , wherein the one or more processing circuits are configured to decide to use the first type of signal quality determination instead of the second type of signal quality determination in response to a control indicator received from the communication network. 
     
     
         12 . The wireless communication device of  claim 9 , wherein the one or more processing circuits are configured to decide to use the first type of signal quality determination instead of the second type of signal quality determination in one or more of the following cases:
 network configuration information received or determined by the wireless communication device indicates that two or more cells in the network that are of interest with respect to signal quality determination have overlapping downlink carrier frequencies but have different bandwidths and/or different center frequencies; and   measurement requirements information received or determined by the wireless communication device indicates that the first type of signal quality determination is preferred.   
     
     
         13 . The wireless communication device of  claim 7 , wherein the downlink carrier is an Orthogonal Frequency Division Multiplexed (OFDM) carrier and wherein the first and second frequency regions comprise different sets of resource blocks of the OFDM carrier. 
     
     
         14 . The wireless communication device of  claim 7 , wherein the one or more processing circuits are configured to determine the signal quality of two or more downlink carriers of two or more cells in the communication network, said two or more cells being any mix of neighboring and serving cells with respect to the wireless communication device. 
     
     
         15 . The wireless communication device of  claim 7 , wherein the one or more processing circuits are configured to determine signal quality as one or more of: a Reference Signal Received Quality, “RSRQ”, a Reference Signal Received Power, “RSRP”, and a Received Signal Strength Indicator, “RSSI”. 
     
     
         16 . A network node configured for operation in a communication network, said network node characterized by:
 one or more communication interfaces for sending an indicator to a wireless communication device, to control whether a wireless communication device determines a signal quality for a downlink carrier of a cell in the communication network using a first type of signal quality determination, or a second type of signal quality determination; and   a control circuit configured to control said indicator to indicate that the first type of signal quality determination is to be used when:
 two or more cells in the network that are of interest with respect to signal quality determination by the wireless communication device have overlapping downlink carrier frequencies but have different bandwidths and/or different center frequencies; or 
 more accurate signal quality determinations are required, as is indicated by measurement requirements information. 
   
     
     
         17 . The network node of  claim 16 , wherein the network node is configured to receive and recognize a return indicator from the wireless communication device, indicating use of the first type of signal quality determination by the wireless communication device. 
     
     
         18 . A method of controlling the type of signal quality determination used by a wireless communication device, said method implemented in a network node of a communication network, and characterized by:
 sending an indicator to a wireless communication device, to control whether the wireless communication device determines a signal quality of a downlink carrier of a cell of the network using a first type or a second type of signal quality determination; and   controlling said indicator to indicate that the first type of signal quality determination is to be used, when:
 two or more cells in the network that are of interest with respect to signal quality determination by the wireless communication device have overlapping downlink carrier frequencies but have different bandwidths and/or different center frequencies; or 
 more accurate signal quality determinations are required, as is indicated by measurement requirements information. 
   
     
     
         19 . The method of  claim 18 , further comprising receiving and recognizing a return indicator from the wireless communication device, indicating use of the first type of signal quality determination by the wireless communication device.