Method of quadrature spreading

A method of quadrature spreading by an M bit processor in a code division multiple access communication (CDMA) system, the method comprising:

• adding a bit of each of N data channels together to obtain a combined channel value represented by K bits where K is the smallest number of bits which is required to represent N in binary and which is a factor of M;
• packing S combined channel values into an M bit combined channel data element, where S×K=M;
• extending M/N bits of short code to M bits by repeating each bit of short code N times to produce an extended short code;
• and
• XORing the combined channel data element with the extended short code to obtain an N channel M bit spread channel value, wherein the XORing comprises a spreading operation:
• X
• out
• =
• {
• X
• in
• if
• ⁢
• ⁢
• the
• ⁢
• ⁢
• bit
• ⁢
• ⁢
• of
• ⁢
• ⁢
• short
• ⁢
• ⁢
• code
• =
• 0
• N
• -
• X
• in
• if
• ⁢
• ⁢
• the
• ⁢
• ⁢
• bit
• ⁢
• ⁢
• of
• ⁢
• ⁢
• short
• ⁢
• ⁢
• code
• =
• 1
• and wherein said spreading operation is performed by:
• providing constant data having M bits in which a binary sequence representing the number of channels N is repeated S times;
• performing a first manipulation of said combined channel data by logically AND-ing said combined channel data with said short code data to thereby obtain first manipulated combined channel data;
• performing a second manipulation of said combined channel data by (a) subtracting said combined channel data from said constant data to obtain first intermediate data and (b) logically AND-ing said intermediate data with the inverse of said short code data to thereby obtain second manipulated combined channel data;
• logically OR-ing said first and second manipulated combined channel data;
• and subtracting said logically OR-ed first and second manipulated combined channel data from said constant data to obtain said spread channel data.