# Transmitter Diversity Gain Technique Aided Irregular Channel Coding for Mobile Video Transmission
## 3 Preliminaries & System Design Criteria  
The STBC technique requires channel estimation and uses coherent detection. The channel experiences an increase in the complexity and cost of the receiver due to the channel estimation technique. In comparison to this scheme, DSTS is constituted, which does not require any channel estimation technique. DSTS is a specific scheme for low computational complexity Multiple Input Multiple Output (MIMO) systems by using a non-coherent detection method. DSTS consists of a differential encoder and a space time spreading encoder (STS). Space time spreading codes was originally designed as a transmitter diversity technique for the downlink of Code Division Multiple Access (CDMA) systems. A small  
\begin{table}
\begin{tabular}{p{142.3 pt} p{142.3 pt} p{142.3 pt}} \hline \hline
**Year** & **Author** & **Contributions** \\ \hline
1948 & [PERSON] [12] & Established a relationship between block size, transmission rate, channel capacity, and error probability. \\ \hline
1950 & [PERSON] [13] & Utilized first error detecting and single error correcting codes through redundancy \\ \hline
1952 & [PERSON] [40] & Compared different signaling alphabets (Performance of signal alphabets is computed and it was concluded that complex alphabets are required in order to transmit a signal close to channel capacity.) \\ \hline
1955 & [PERSON] [14] & Presented Convolutional codes \\ \hline
1993 & [PERSON] et al. [15] & Presented turbo codes \\ \hline
1999 & [PERSON] [21] & Proposed EXIT charts for analyzing the convergence behavior of iterative decoding and demapping \\ \hline
2002 & [PERSON] and [PERSON] [24] & Proposed irregular convolutional codes as well as simplified method for computing mutual information in EXIT Chart analysis \\ \hline
2003 & [PERSON] et al. [8] & Proposed Sphere Packing (SP) modulation \\ \hline
2008 & [PERSON] et al. [10] & Proposed Differential Space Time Spreading (DSTS) codes \\ \hline
2016 & [PERSON] et al. [32] & Implemented Fully Parallel Turbo Decoder (FPTD) on hardware design \\ \hline
2020 & [PERSON] et al. [30] & Analyzed the convergence behavior of Self-Concatenated Convolutional Codes (SECCs) \\ \hline Proposed work & [PERSON] et al. & \
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\begin{tabular}{p{142.  
number of Tx antennas at the base-station and one or more Rx antennas at the handset improved the performance by introducing a novel spreading codes while using the space-time codes. Constellation signals are spread in a balanced way to provide full diversity path gain at the receiver. The STS approach was designed to increase the bit rate and improve the quality and range in the downlink of either mobile or fixed CDMA systems [4]. The STS scheme divides the user data stream into two odd and even sub-streams, i.e., \(b_{1}(i)\) and \(b_{2}(i)\) refer to Figure 1 and produces the signals at both the transmitting antennas using orthogonal set of \(c_{1}\) and \(c_{2}\) unit norm spreading of a \(2P\times 1\) length, as given below:  
\[t_{1}=\frac{1}{\sqrt{2}}(b_{1}c_{1}+b_{2}c_{2}) \tag{1}\]  
\[t_{2}=\frac{1}{\sqrt{2}}(b_{2}c_{1}-b_{1}c_{2}) \tag{2}\]  
The differential encoder take place before STS and then the encoded symbols are spread by using STS, where two symbols are transmitted while using two transmitter antennas. Initially, two dummy symbols \(\mathbf{V}_{0}^{1}\), \(\mathbf{V}_{0}^{2}\) are transmitted having no information and, afterwards, the bit-stream \(x_{t}^{k}\); \(k=1,2\) at the bit-mapper are divided into \(\mathbf{V}_{t}^{1}\) and \(\mathbf{V}_{t}^{2}\) symbols refer to Figure 2. The differential encoded symbols are represented, as in [10,11].