Difference Between IDEN vs CDMA Network Technology
IDEN (Integrated Digital Enhanced Network)
This is a wireless network technology being developed by Motorola in which the following capabilities of other networks are tied together. Among them the capabilities of Digital Cellular networks, fax and modem facilities and two ways radio is included.
The operating frequency of the network is actually divided in to three bands namely 800 MHz, 900 MHz and 1500 MHz with TDMA being the multiple access technique as deployed in GSM networks. The duplex distance for the network depends on the frequency band being operating and it is 39 MHz, 45 MHz and 48 MH respectively.
The voice compression is achieved via Motorola’s proprietary vocoder known as Vector Sum Excited Linear Predictors along with QAM (Quadrature Amplitude Modulation) as the digital modulation scheme. The channel band width of the IDEN is 25 kHz in which it can effectively deliver 64kBps data rate for voice transmission. With this data rate IDEN supports six simultaneous users per channel or six push to talk users per channel.
The currently utilized IDEN handsets use SIM cards which are obviously in accessible in GSM networks and handsets. The signaling system utilized in IDEN is similar to GSM signaling which is being modified for the requirements of IDEN and called as Mobis.
This is the multiple access technique used by communication systems in which the well known TDMA and FDMA techniques are combined together to form the new technique and can be regarded as a hybrid version of above technologies. The most significant feature of the technique is that a secured communication is achieved by utilizing a pseudo-noise sequence for each subscriber and this technique is also known as direct sequence spread spectrum technology.
This secured communication is achieved by means of converting the original digital signal directly in to much higher frequency by utilizing a pseudo random noise signal. As a result of the direct conversion of the signal in to higher frequency the spectrum of the original signal is flattened (spread) in the frequency domain hence the name spread spectrum. As a consequence of that the signal is visible as a noise without the correct pseudo-noise code at the receivers end. This has allowed increasing the number of subscribers in a given cell and more secured communication is available.
CDMA is used with 800 MHz band and 1900 MHz bands with the channel bandwidth lies around 1.25 MHz. The original CDMA standard is known as CDMA one and it is capable of providing data rates up to 14.4 kbps in single channel and 115 kbps with eight channels. Then in the next phases like CDMA 2000, WCDMA is capable of providing data rates in Mbps range which are suitable for 3G and 3.5G networks.
Difference between iDEN and CDMA
1. CDMA uses spread spectrum technique with each receiver having a unique code to encode and decode signals.
2. iDEN utilizes TDMA whilst CDMA utilize both TDMA and FDMA together allowing much more simultaneous calls.
3. iDEN data rates are limited to 64 kbps whilst CDMA varieties(CDMA 2000, WCDMA) provides much more higher data rates in Mbps range.
4. iDEN channel bandwidth is 25 kHz and CDMA channel bandwidth is around 1.25 MHz and goes up to 5 MHz in WCDMA.