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How Transport Channel Processing in LTE?

How Transport Channel Processing in LTE? Transport channels are block oriented transmission services and transmit one or more transport blocks per transmission time interval (TTI). The TTI is 1 ms (e.g. one sub-frame). Transport blocks may in general have variable size. Typically the number of transport blocks that can be transmitted in a TTI depends … Read more

What is the difference between 4G and 4G LTE?

What is the difference between 4G and 4G LTE? Many people use the terms 4g and 4g interchangeably, but they are not the same. Lets find out the difference…. Features of 4g 4G is the next step above and a 3g replacement, offering faster speeds for users who stream media (such as videos or mp3s), … Read more

How Voice Signal Processing in GSM

How Voice Signal Processing in GSM The radio channel is quite different from the wired channel. First, the radio channel has a distinct time-change characteristic. The radio channel is exposed to the air, so it is vulnerable to the  interferences in the air. The signal is influenced by various interferences, multi-path fading and shadow fading, … Read more

Processing Procedure of WCDMA System

Processing Procedure of WCDMA System Source coding can increase the transmitting efficiency. Channel coding can make the transmission more reliable. Spreading can increase the capability of overcoming interference. Through the modulation, the signals will transfer to radio signals from digital signals. Bit, Symbol, Chip Bit : data after source coding Symbol: data after channel coding … Read more

Forward Power Control in CDMA

Message Transmission Mode MS measures the frame quality and informs the base station to the result i.e. whether it is in the threshold or periodical  mode. Base station determines whether  to change the forward transmitting power or not. In IS-95 system, the forward power control is slow but in CDMA2000 system it is fast. Forward … Read more

LTE Frame Structure and Resource Block Architecture

LTE Frame Structure The figure below shows the LTE frame structure under Time division mode (TDD) Type 2 and Frequency Division mode (FDD) Type 1. Differences in LTE Frame Structure Main differences in LTE Frame Structure between the two modes are Frame 0 and frame 5 (always downlink in TDD) Frame 1 and frame 6 … Read more

How Modulation-QPSK in CDMA ?

     In an actual application, the system implements the modulation in this way:  as shown above, I and Q channel sequences in the figure represent two channels of cyclic PN short code sequences.  The cyclic period of each channel of PN short codes is 215. For different sectors, there are different starting locations of I … Read more

What is Interleaving

  If the voice signal is modulated and transmitted directly after channel coding, due to the condition changes in mobile communication channel, a deep of the fading will influence a successive string of bits and cause high bit error rate. If the bits of a successive string are interfered or lost, the other end of … Read more

Frequency Hopping

When the voice signal is transmitted after being processed and modulated, the frequency hopping technique will be used too, i.e. the transmission carrier varies constantly at different timeslots (of course, the variation should comply with the frequency planning principles). The frequency hopping spread spectrum (FHSS) is a method for quickly switching the transmission of radio … Read more

Burst in GSM

The Logical  Channel is used in time multiplex in a physical channel, which is categorized according to the types of messages transmitted in the physical channel. Different logical channels are used in transmission of different types of information between BS and MS, such as the signaling or traffic data. In GSM system, five different types … Read more