top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

Why Turbo Encoder is used for data channels ? I mean what it specifically does?

+2 votes
735 views
Why Turbo Encoder is used for data channels ? I mean what it specifically does?
posted Jun 9, 2014 by Prithvi

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button

1 Answer

0 votes

The Turbo encoder in LTE is a systematic parallel concatenated convolution code (PCCC) with two 8-state constituent encoders and one Turbo code contention free internal inter-leaver. Where the encoders are based on RSC (Recursive Systematic Convolution) codes and their generator polynomial is given by

G=[1, g0/g1], 

where g0=[1011] (feedback) and g1=[1101] (feedforward).

Structure of the LTE Turbo encoder (dotted lines are for trellis termination:

Turbo Ensoder in LTE

As can be seen in Figure the output of the LTE Turbo encoder consists of three parts, a systematic bit and two parity bits. The systematic bit is the untouched input bit. The first parity bit is the output of the first convolution encoder with the original input as input and the second parity bit is the output of the second convolution encoder after interleaving.

Turbo coding is used in LTE for following channels: UL-SCH (Uplink Shared CHannel), DLSCH (Downlink Shared CHannel), PCH (Paging CHannel) and MCH (Multicast CHannel).

answer Jun 10, 2014 by Manish Tiwari
Similar Questions
+1 vote

why QPSK modulation scheme is used for all control channels in LTE ?

0 votes

Why separate channels are required for HARQ?Why PHICH is used for ACK/NACK why not PDCCH channel is used?

0 votes

What could be the reason for defining logical channel grouping concept in LTE ? Why logical channels can't be used independently ?

...