Difference Between CDMA and LTE Network Technology

CDMA vs LTE Network Technology

CDMA (Code Division Multiple Access) and LTE (Long Term Evolution) are different in sense that CDMA is a multiple access technology whilst LTE is the next generation mobile communication standards (4G). Multiple access technologies are utilized in mobile networks in order to support more users per cell with limited resources. TDMA, FDMA are the first technologies of such kind and later CDMA is developed, which utilizes all the resources for everyone in the network. LTE is defined by the 3GPP (3rd Generation Partnership Project) in order to cater the demand of higher data rates needed for multimedia applications, high speed internet access etc by the mobile users and making the pathway for mobile broadband a reality.

CDMA

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. In this case it 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.

LTE

LTE can be considered as the 4G of mobile communication standards which are a project of 3GPP (third generation partnership project) started on 2004 and completed its release 8 in 2009. The following radio technologies are being used MIMO (Multiple Input Multiple Output), OFDMA (Orthogonal Frequency Division Multiple Access) and SC-FDMA (Single Carrier FDMA).

By utilizing MIMO in mobile communication systems it improves radio channel capacity in mobile communication systems hence recommended by 3GPP in order to achieve high data rates. OFDMA is the multiple access technology to be used with LTE and in order to achieve a downlink around 100 Mbps range and it is the most promising technique currently available due to its simple receiver structure and spectral efficiency. LTE has downlink peak rates around 360 Mbps whilst uplink is around 86 Mbps with a channel bandwidth of 20 MHz which is scalable from 1.25MHz to upwards. Also the round trip time from base station to mobile station is improved with 10 ms range.

SC FDMA is similar to OFDMA except that it uses some additional DFT processing and currently this is recommended by the 3GPP to be used as the uplink communication methodology due to transmission power efficiency and cost concerning of mobile equipments.

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