The disclosed invention is referred to a method for optimising the
random access procedures in
third generation CDMA cellular
telephony systems. The particular embodiment of the example concerns a TD-SCDMA-TDD synchronous realization. The disclosed procedure includes a preliminary part charged to the network (BSSC, MSC) only for establishing the following associations between the configuration parameters of the involved physical channels: one signature burst (
SYNC1) is associated to one forward access channel (P-FACH) only, in order to avoid any,
ambiguity in the mobile stations about where to look for the expected
acknowledgement from the network; one
random access common channel (P-RACH) is associated to one forward access channel (P-FACH) only, in order to reduce collision on the latter (P-RACH); one access grant channel (P / S-CCPCH, AGCH) only is associated to one
random access common channel (P-RACH), in order to avoid any
ambiguity in the mobile stations about where to look for the expected answer from the network with the indication of the dedicated service channels (DPCH); and each complete associative link binding the involved physical channels is included in the
system information and broadcasted into the serving
cell to be read by the mobile stations (MS, UE) when entering an actual part of the procedure charged to
exchange protocol messages with the network (BSSC, MSC) through said associative links that being signalling at once to the mobile stations the
route towards the services offered by the network, simplifying the access procedure consequently. Suitable groupings among: Downlink
pilot sequences, Uplink
pilot sequences, scrambling codes, basic midambles, are carried out in a
cell-discriminating way and broadcasted into the
cell to simplify the serving
cell selection procedure (<cross-reference target="DRAWINGS">FIG. 1< / cross-reference>).