Spectrum spreading or despreading device, in particular for transmission in a code division multiple access cellular mobile radio system

Device for despreading an incoming sequence using K respective spreading codes of respective length Qk (with 1≦k≦K), the device including, for despreading the incoming sequence using each of the spreading codes of length Qk (1≦k≦K):

• means for distributing the data symbols of the incoming sequence into different sub-sequences, and
• means for despreading each of these sub-sequences by means of a spreading code of length Q0 which is a multiple of the length Qk,
• said sub-sequences and said spreading codes of length Q0 that are applied to them being determined so that the sequence that would be obtained by superposing the despread sub-sequences obtained in this way is the same as that which would be obtained by despreading the incoming sequence using the code of length Qk,
• and said length Q0 being common to the K codes.

Device for spreading K incoming sequences using K respective spreading codes of respective length Qk (with 1≦k≦K), the device including, for spreading the kth incoming sequence by means of the spreading code of length Qk (1≦k≦K):

• means for distributing the data symbols of the incoming sequence into different sub-sequences, and
• means for spreading each of these sub-sequences by means of a spreading code of length Q0 which is a multiple of the length Q of the code,
• said sub-sequences and said spreading codes of length Q0 that are applied to them being determined so that the sequence that would be obtained by superposing the different spread sub-sequence obtained in this way is the same as that which would be obtained by spreading the incoming sequence using the code of length Qk,
• and said length Q0 being common to the K codes.