Resource allocation to users in slotted code division multiple access systems using beams

Abstract

The invention includes several embodiments for slot assignment in code division multiple access communication systems. Some of the embodiments relate to fixed beams and others relate to adaptive arrays. One embodiment for fixed beams assigns slots by first detecting a beam having the best received quality and selected the best slot from that beam. Another fixed beam embodiment determines the best slot or slots in a number of beams and determines the overall best beam/slot combination. Another fixed beam embodiment uses a modified interference factor. One embodiment for the uplink using adaptive arrays using a spatial analysis stage followed by a transmission power level estimation stage. An overall interference level associated with each slot is determined and a slot having the best overall quality is determined. Another embodiment for the downlink uses the spatial analysis and slot assignment of the uplink for the downlink. Another embodiment for the downlink uses a spatial and transmission power level estimation stages. For adaptive arrays, the slot assignment can be determined whether the pathloss for each user is estimated or not and whether signals from each user are received or not.

1 . A method for assigning time slots in slotted code division multiple access communication systems having an adaptive array, the method comprising:
 for each time slot, determining antenna patterns and associated antenna gains;   for each time slot, determining a transmit power associated with each user using the determined associated antenna gains;   iteratively repeating the determining antenna patterns and the determining transmit power; and   selecting a slot for assignment having a lowest aggregate interference, the lowest aggregate interference determined using the determined transmit power for each slot.   
   
   
       2 . The method of  claim 1  wherein the repeating is performed until the determined antenna patterns and the determined transmit power substantially converge. 
   
   
       3 . The method of  claim 1  wherein the repeating is performed a predetermined number of times. 
   
   
       4 . The method of  claim 1  wherein the determined antenna patterns is based on a covariance base algorithm. 
   
   
       5 . The method of  claim 1  wherein the determined antenna patterns is based on a direction based algorithm. 
   
   
       6 . The method of  claim 1  wherein the determined transmit power is determined using a desired signal to interference ratio for links. 
   
   
       7 . The method of  claim 1  wherein the selected time slot is an uplink time slot. 
   
   
       8 . The method of  claim 7  further comprising selecting a downlink time slot corresponding to a user of the selected uplink time slot based on the selected uplink time slot. 
   
   
       9 . The method of  claim 8  wherein weights of the determined antenna patterns as determined for the uplink are used for downlink antenna patterns. 
   
   
       10 . The method of  claim 1  wherein the selected time slot is a downlink time slot. 
   
   
       11 . A method for assigning time slots in slotted code division multiple access communication systems having an adaptive array, the method comprising:
 for each time slot:
 determining antenna gains for a new and other users; 
 determining transmit power levels of the new and other users using the determined antenna gains; 
 redetermining antenna gains for the new and other users using the determined transmit power levels; 
 repeating the determining transmit powers and the redetermining antenna gains; and 
 determining a total transmit power using the determined transmit power levels; and 
   selecting a time slot having a lowest total transmit power for assignment.   
   
   
       12 . A method for assigning time slots in slotted code division multiple access communication systems having an adaptive array, the method comprising:
 for each time slot:
 determining antenna gains for a new and other users; 
 determining a transmit power level of the new user using the determined antenna gains; 
 redetermining antenna gains for the new and other users using the determined transmit power level; 
 measuring received signal levels using the redetermined antenna gains; 
 repeating measuring received signal levels and redetermining antenna gains; and 
 determining a total received signal level using the redetermined antenna gains; and 
   selecting a time slot having a lowest total received signal level for assignment.