Method and apparatus for assigning spreading codes

Abstract

A method is taught for transmitting message signals in a communication system having a new call entering tile communication system and Walsh codes that can be active and inactive. The method includes dividing the Walsh codes into bins and determining the number of active Walsh codes in the bins. Selecting a Walsh code in accordance with the Walsh code number determination and assigning the selected Walsh code to the new call are set forth. The Walsh codes have indices and the Walsh codes are divided into bins according to the indices. The Walsh codes are divided into cycles according to the indices and if the number of bins is n the Walsh codes are divided into bins in accordance with the value of their indices modulo n. The minimum number of active Walsh codes in the bins is determined and the Walsh code is selected in accordance with the minimum number of active codes. A plurality of the bins can contain the minimum number of active Walsh codes. The method also sets forth selecting a bin of the plurality of bins containing the minimum number of active Walsh codes and selecting a Walsh code from the selected bin. A subset of the bins containing the minimum number of active Walsh codes is selected and a first predetermined bin with a preference lower than a preference for the remaining bins of the subset of the bins is selected.