CDMA Technology
Members Sign-In
CDMA2000 1X Interface

The following fundamental CDMA air interface techniques are incorporated into CDMA2000 1X and backward compatible with cdmaOne:

  • Direct Sequence Spread Spectrum Multiple Access: to improve spectral efficiency (system capacity)
  • Orthogonal Code Channelization: for user separation on the downlink (mitigates interference)
  • Random Access: to efficiently share radio access resources among all users
  • Fast Uplink Power Control: to resolve the near-far field effect (reduce interference)
  • Rake Receivers: to resolve and benefit from multipath interference and support soft handoffs
  • Soft Handoff: to handoff users between base stations
  • Softer Handoff: to handoff users between base station sectors
  • Soft Handoff (SHO) Active Set: to provide seamless service with increased spectral efficiency
  • Single Frequency Re-use: to increase overall network capacity
  • Downlink Slotted Paging: to extend the battery life of mobile devices
  • Blind Rate Detection: to enable variable rate decoding without additional overhead
  • Downlink Reference Channel: to share a common pilot to increase capacity
  • Downlink Channel Structure: to simplify system implementation and efficiency by separating channels with Walsh codes
  • Scrambling: to provide communications privacy
  • Speech Regulated Vocoders: to reduce interference and increase system capacity
In addition to the above techniques shared with cdmaOne, CDMA2000 1X incorporates the following evolutionary air interface techniques that are crucial to enhancing the performance of the standard:
  • Variable Length Orthogonal Codes: to support variable data rates
  • Uplink Complex Spreading: to increase data rates and network capacity
  • Fast Downlink Power Control: to reduce transmit power usage and increase capacity
  • Data Rate Configurable Channels: to support applications that use a variety of data rates
  • Dual-Event Downlink Paging: to further extend the battery life of mobile devices
  • Uplink Channel Structure: to multiplex control and data channels
  • Reserve Mode Random Access: to access the network more efficiently
  • Parallel Turbo Codes: to improve capacity through more efficient forward error correction
  • Coherent Uplink Detection: to improve data rates and coverage
  • Continuous Uplink Operation: to increase transmission range and capacity, while reducing interference to hearing aids and other devices