# Performance Analysis of a Novel TCP Protocol Algorithm Adapted to Wireless Networks
## 5 Conclusion and Future Work  
Since the TCP protocol was designed to work in wired networks, its performance is not adequate for wireless networks, where the packets corrupted for interference, obstacles or fading are discarded and taken as a fictional congestion con- sequence. This assumption entails to an unnecessary CWND reduction which decreases the transmission bit rate.  
In this paper, we proposed a TCP-NACK protocol that endures wireless performance problems by the incorporation of an error notification or \"NACK\" to the Generic TCP protocol functionality. This notification indicates to the transmitter the arrival of corrupted packets, proceeding to an immediate re- transmission without the CWND reduction. For its validation, we exposed the mathematical analysis, configurations to the Linux source code, emulation, and the testbed analysis in real scenarios.  
The results obtained demonstrate a better performance of TCP-NACK protocol against its generic counterpart (TCP Reno) under different scenarios including different distances, bandwidths, packet error rates and technologies employed. Regardless of the fact that the experimental results obtained are lower than the mathematical results, we achieved an average improvement of 54% in \(\overline{\theta}\), 26% in \(\delta\), and 5% in jitter when compared to Generic TCP. It is important to highlight that we obtained the best \(\overline{\theta}\) results between 100 and 414 m, where, on average, there is an improvement of 90%. The principal differences among our work and those described in the literature are the performance evaluation as a function of the distance, and the experimentation tests over networks with exclusively wireless links.  
Figure 12: Long distance results: (**a**) \(\overline{\theta}\); (**b**) \(\delta\); (**c**) jitter.  
In summary, TCP-NACK is a good option for wireless networks, and it is perfectly attachable to any personal computer as a modified Linux operating system. This proposal was evaluated under several real conditions and demonstrated high improvements when compared with TCP Reno protocol.  
As future works we are interested in considering the communication standard, frequency and the running application (e.g., VoIP) as variables. We are also interested in performing tests with larger distances and bandwidths evenly distributed. We are also planning to include tests with an optimization of the RTT calculation, by applying the mathematical modeling described in [24] with the aim of improving the \(\theta\) values for wireless links with short and long distances. Finally, we are interested in comparing with other proposals which are available to be implemented in open hardware.  
Conceptualization, G.O. and C.d.A.; methodology, R.L.-C. and G.O.; validation, R.L.-C., G.O. and D.M.; formal analysis, R.L.-C.; investigation, G.O., R.L.-C.; writing--original draft preparation, D.M., writing--review and editing, R.L.-C.; visualization, G.O.; funding acquisition, R.L.-C. and G.O.; All authors have read and agreed to the published version of the manuscript.  
This research was funded by Universidad de las Fuerzas Armadas ESPE, grants number 2010-PIT-008 and 2012-PIT-020.  
The authors would like to thank grateful to Dr. [PERSON], Colegio de Ciencias e Ingenierias, Universidad San Francisco de Quito USFQ, for proofreading this document. And last but not least, this work might not have been possible without the efforts of the Grupo de Investigacion de Sistemas Inteligentes (WiCOM energy), and Centro de Investigaciones de Redes Ad-Hoc (CIRAD).  
The authors declare no conflict of interest.