is transmitted through iub 104 to the mac c sh or rnc 308 as a r99 prach data packet otherwise the data packet is discarded 306 as a corrupted r99 prach data packet or a different data packet type it should be understood that although in fig4 e prach decoding is performed prior to r99 prach decoding the order in which sequential decoding of e prach and r99 prach are performed may be reversed a common u201c front end u201d prach data packet identification and demodulation mechanism 302 in fig3 and 4 may be used for both e prach and r99 prach data packets if the physical channel structures are similar this is a preferred embodiment due to the use of this common front end detection procedure the probability of detecting an e prach or a r99 prach data packet given nothing was transmitted are not affected some reliabilities of interest include i p e 99 the probability of detecting an e prach given a r99 prach was transmitted and ii p r99 e the probability of detecting a r99 prach given an e prach was transmitted these probabilities are a complex function of the various constituent functional blocks of the transport channel processing chains such as for example the type of forward error correction the rate matching applied to each rach type the length of the crc employed however the e prach transport channel processing and encoding can be designed such as to ensure low probabilities p e 99 and p r99 e it is preferable to leave the transport channel processing applied to r99 prach.