CDMA 2000 1X

• Walsh sequence is used in the forward channel of IS-95 and CDMA2000 system, while the orthogonal variable spreading factor, OVSF sequence is used in WCDMA system
  

• the CDMA2000 1X packet services, the system needs to establish corresponding auxiliary code division channels in addition to the forward and reverse fundament traffic channels. If the forward links require a lot of packet data transfer, BS will send the auxiliary channel assignment information to establish the corresponding forward auxiliary code division channel, thus enabling the data to be sent to MS via the forward auxiliary code division channel within the time period designated by the information. If the reverse links require a lot of packet data transfer amount, MS will send the auxiliary channel request information to establish the corresponding reverse auxiliary code division channel with BS, thus enabling the data to be sent to BS via the reverse auxiliary code division channel within the time period designated by the information. Self-evidently, the auxiliary channel establishment enables CDMA2000 1X to be more flexible in supporting the packet services.