Method of sequencing signal processing in the reduced rate communication mode of a digital cellular radio system

Method of sequencing signal processing in a digital cellular radio system having a reduced rate communication mode for conveying digitized speech over a communication channel between at least two terminals and a base station, said radio system using multiframes each comprising a sequence of frames, some of said frames being used for conveying digitized speech and being designated as traffic frames, said digitized speech comprising coded blocks each representing a single group of speech samples, each coded block being formed of 2.multidot.s sub-blocks, a pth sub-block of a coded block and a (p+s)th sub-block of a preceding coded block being combined in a pth packet conveyed during a pth traffic frame, each said multiframe comprising k groups of 2.times.s consecutive frames, each of said k groups of 2.times.s consecutive frames including only s traffic frames, any traffic frame being identified within its respective said multiframe by the expression s.multidot.j+p, each of said traffic frames comprising at least two disjoint time slots including a first time slot for a send packet and a second time slot for a receive packet, said method comprising the following steps during each group j of said k groups of 2.times.s consecutive frames:

• during each traffic frame s.multidot.j+p, processing a pth receive packet in a respective receive time slot by recovering the pth receive sub-block of a (j+n)th coded receive block and the (p+s)th receive sub-block of a (j+n-1)th coded receive block, and processing a pth send packet in a respective send time slot by combining a pth send sub-block of a (j+n)th coded send block and a (p+s)th send sub-block of a (j+n-1)th coded send block;
• during a send period, forming a next (j+n+1)th coded send block from a group of speech samples to be sent;
• and
• during a receive period, recovering a prior (j+n-2)th coded receive block and recovering any corresponding speech samples contained therein,
• where
• s is a positive integer representative of the number of sub-blocks in a coded block divided by 2,
• k is a positive integer representative of the number of coded blocks in a multiframe,
• j is a first integer variable 0.ltoreq.j<k representative of the position of a coded block within a multiframe,
• n is a second integer variable representative of the rank of the coded send block whose first sub-block is sent on the first frame of said current multiframe, and
• p is a third integer variable 0<p.ltoreq.s representative of the position of a sub-block within a coded block.