Code allocation based on cross code correlation

Abstract

The invention includes various approaches to assigning codes in wireless code division multiple access communication systems. The invention estimates the cross code correlation between codes to base the code assignment. One approach assigns codes having a high cross correlation to users having a low transmission power level. Another approach assigns code groups having a high cross correlation to a same coded composite transport channel. Another approach assigns codes using a cross correlation factor of each code to minimize a system noise rise. Another approach uses transmission or reception diversity to assign bad code groups to users having a different diversity relationship. Another approach uses a diversity factor and a cross code correlation factor to assign codes.

1 . A method for assigning codes to communications in a wireless code division multiple access communication system using spatial diversity, the method comprising: 
 providing codes for potential assignment;    determining users having a different diversity relationship;    evaluating the provided codes to determine bad groups of codes having a high cross code correlation; and    assigning the provided codes to users, such that if codes of one of the bad code groups are to be assigned, those bad code group codes are preferably assigned to the users determined to have a different diversity relationship.    
     
     
         2 . A wireless code division multiple access radio network controller (RNC) comprising: 
 means for determining users having a different diversity relationship;    means for evaluating provided codes for potential assignment to determine bad groups of codes having a high cross code correlation; and    means for assigning the provided codes to users, such that if codes of one of the bad code groups are to be assigned, those bad code group codes are preferably assigned to the users determined to have a different diversity relationship.    
     
     
         3 . A wireless code division multiple access radio network controller (RNC) comprising: 
 a code assignment device for determining users having a different diversity relationship; for evaluating provided codes for potential assignment to determine bad groups of codes having a high cross code correlation; and for assigning the provided codes to users, such that if codes of one of the bad code groups are to be assigned, those bad code group codes are preferably assigned to the users determined to have a different diversity relationship.    
     
     
         4 . A wireless code division multiple access user equipment (UE) comprising: 
 an assigned codes determination device for determining codes assigned to support communications of the UE, the code assignment determined by determining users having a different diversity relationship; evaluating provided codes for potential assignment to determine bad groups of codes having a high cross code correlation; and assigning the provided codes to users, such that if codes of one of the bad code groups are to be assigned, those bad code group codes are preferably assigned to the users determined to have a different diversity relationship.    
     
     
         5 . A method for assigning codes to communication in a wireless code division multiple access communication system using spatial diversity, the method comprising: 
 providing codes for potential assignment and codes currently used by users;    determining a diversity factor for each user using a direction of arrival of signals received at a base station of that user;    determining a cross correlation factor for each provided code, the cross correlation factor indicating a cross code correlation between that provided code and other codes;    determining an optimal code assignment based on the diversity and cross code correlation factors; and    assigning the provided codes to users based on the optimal code assignment.    
     
     
         6 . The method of  claim 5  wherein the determining an optimal code assignment is based on a product of the diversity and the cross code correlation factors.  
     
     
         7 . The method of  claim 5  wherein the code division multiple access communication system is a time division duplex communication system using code division multiple access and the optimal code assignment minimizes a weighted average of an estimated reception quality over all time slots.  
     
     
         8 . The method of  claim 5  wherein the code division multiple access communication system is a time division multiple access communication system using code division multiple access and the optimal code assignment minimizes a weighted average of an estimated reception quality over all time slots.  
     
     
         9 . The method of  claim 5  wherein the code division multiple access communication system is a time division duplex communication system using code division multiple access and the optimal code assignment is a joint solution to minimize a weighted average of an estimated reception quality over all time slots and maximize each user reception quality.  
     
     
         10 . The method of  claim 5  wherein the code division multiple access communication system is a time division multiple access communication system using code division multiple access and the optimal code assignment is a joint solution to minimize a weighted average of an estimated reception quality over all time slots and maximize each user reception quality.  
     
     
         11 . A wireless code division multiple access radio network controller (RNC) comprising: 
 means for determining a diversity factor for each user using a direction of arrival of received signals of that user;    means for determining a cross correlation factor for each provided code for potential assignment, the cross correlation factor indicating a cross code correlation between that provided code and other codes;    means for determining an optimal code assignment based on the diversity and cross code correlation factors; and    means for assigning the provided codes to users based on the optimal code assignment.    
     
     
         12 . The RNC of  claim 11  wherein the determining an optimal code assignment is based on a product of the diversity and the cross code correlation factors.  
     
     
         13 . The RNC of  claim 11  wherein the RNC is a time division duplex using code division multiple access RNC and the optimal code assignment minimizes a weighted average of an estimated reception quality over all time slots.  
     
     
         14 . The RNC of  claim 11  wherein the RNC is a time division multiple access using code division multiple access RNC and the optimal code assignment minimizes a weighted average of an estimated reception quality over all time slots.  
     
     
         15 . The RNC of  claim 11  wherein the RNC is a time division duplex using code division multiple access RNC and the optimal code assignment is a joint solution to minimize a weighted average of an estimated reception quality over all time slots and maximize each user reception quality.  
     
     
         16 . The RNC of  claim 11  wherein the RNC is a time division multiple access using code division multiple access RNC and the optimal code assignment is a joint solution to minimize a weighted average of an estimated reception quality over all time slots and maximize each user reception quality.  
     
     
         17 . A wireless code division multiple access radio network controller (RNC) comprising: 
 means for determining a diversity factor for each user using a direction of arrival of received signals of that user;    means for determining a cross correlation factor for each provided code for potential assignment, the cross correlation factor indicating a cross code correlation between that provided code and other codes;    means for determining an optimal code assignment based on the diversity and cross code correlation factors; and    means for assigning the provided codes to users based on the optimal code assignment.    
     
     
         18 . The RNC of  claim 17  wherein the determining an optimal code assignment is based on a product of the diversity and the cross code correlation factors.  
     
     
         19 . The RNC of  claim 17  wherein the RNC is a time division duplex using code division multiple access RNC and the optimal code assignment minimizes a weighted average of an estimated reception quality over all time slots.  
     
     
         20 . The RNC of  claim 17  wherein the RNC is a time division multiple access using code division multiple access RNC and the optimal code assignment minimizes a weighted average of an estimated reception quality over all time slots.  
     
     
         21 . The RNC of  claim 17  wherein the RNC is a time division duplex using code division multiple access RNC and the optimal code assignment is a joint solution to minimize a weighted average of an estimated reception quality over all time slots and maximize each user reception quality.  
     
     
         22 . The RNC of  claim 17  wherein the RNC is a time division multiple access using code division multiple access RNC and the optimal code assignment is a joint solution to minimize a weighted average of an estimated reception quality over all time slots and maximize each user reception quality.  
     
     
         23 . A wireless code division multiple access user equipment (UE) comprising: 
 an assigned codes determination device for determining codes assigned to support communications of the UE, the code assignment determined by determining a diversity factor for each user using a direction of arrival of received signals of that user; determining a cross correlation factor for each provided code for potential assignment, the cross correlation factor indicating a cross code correlation between that provided code and other codes; determining an optimal code assignment based on the diversity and cross code correlation factors; and assigning the provided codes to users based on the optimal code assignment.    
     
     
         24 . The UE of  claim 23  wherein the determining an optimal code assignment is based on a product of the diversity and the cross code correlation factors.  
     
     
         25 . The UE of  claim 23  wherein the UE is a time division duplex using code division multiple access UE and the optimal code assignment minimizes a weighted average of an estimated reception quality over all time slots.  
     
     
         26 . The UE of  claim 23  wherein the UE is a time division multiple access using code division multiple access UE and the optimal code assignment minimizes a weighted average of an estimated reception quality over all time slots.  
     
     
         27 . The UE of  claim 23  wherein the UE is a time division duplex using code division multiple access UE and the optimal code assignment is a joint solution to minimize a weighted average of an estimated reception quality over all time slots and maximize each user reception quality.  
     
     
         28 . The UE of  claim 23  wherein the UE is a time division multiple access using code division multiple access UE and the optimal code assignment is a joint solution to minimize a weighted average of an estimated reception quality over all time slots and maximize each user reception quality.