Difference between TDMA and CDMA

TDMA technology was recent in more popular in Europe, Asian countries, Japan, whereas CDMA is widely used in North and South America but nowadays both technologies are very popular throughout the world. TDMA emerged and was utilized first but in CDMA is more recent technology gradually replacing TDMA. The main difference between these two techniques is in the way which the user share the same physical channel. This post gives more information about TDMA VS CDMA to better understand this topic.

TDMA:
  • In TDMA all slots are assigned cyclically.
  • Data rate overhead is between 20 to 30 %.
  • Transmission or receiving is allowed for only one user is given slot.
  • The transmission is noncontinuous.
  • All slot are assigned on demand.
  • Due to reduced inter-user interference, power control is less stringent.
  • It is essential to use digital data and also for modulation.
  • Overhead trade-off is the size of data payload and latency.
  • Multiple users are shared with a single carrier frequency.
  • Due to reduced inter-user interference, power control is less transmission.
  • Handoff is made simpler by using non-continuous transmission.
CDMA:
  • Power limited device.
  • Conversion needs to be extracted from the background.
  • It is difficult to distinguishing individuals when GP is low.
  • Fading would be reduced with a wide frequency spectrum.
  • It needs to have separate multipath signals with different delays by chip unit
  • The system performance will be degraded for every user when the total number of users increases.
  • GP is high when people speak a different language, which is easier to distinguish individual speakers.
  • CDMA uses a process called spread spectrum method, which scattering of digital bits in a pseudo-random manner and collecting them for interpretation.
  • While people talking random noise band playing occurs.
  • CDMA allows numerous user to use the channel at the same time while TDMA does not.
A main key difference between TDMA and CDMA:
  • The abbreviation of TDMA is time division multiple access while in CDMA stand for code division multiple access.
  • CDMA is continoous transmission while TDMA is discontinous transmission.
  • TDMA is segmented sending time into disjoint time slot demand driven or it to be fixed patterns whereas when CDMA has spread the spectrum using orthogonal codes.
  • In TDMA system synchronization in the time domain while in FDMA  signal separation using code puls special receivers.
  • In TDMA all terminal are active for short periods of time on the same frequency while in CDMA can be active at the same place at the same moment uninterrupted.
  • CDMA allows numerous users to use the channel at the same time while TDMA does not allow.
  • CDMA still faces some problems, high complexity, lowered expectations, will be integrated with TDMA or FDMA while in TDMA fixed network together with FDMA or SDMA used in many mobile networks.