Ad-hoc networks are a collection of devices (nodes) that want to communicate but don't have fixed infrastructure nor any default organization. Each node in the network is responsible for the dynamic discovery of other nodes to communicate with them directly or through other nodes using routing protocols [1].

The IEEE 802.11 a / g / p amendments are part of the IEEE 802.11 standard for wireless networks, which can be used in ad-hoc scenario and define the characteristics and operation of the medium access control layer (MAC) and the physical layer (PHY) [2].

The PHY layer of the IEEE 802.11 a / g / p standards is based on OFDM transmission (Orthogonal Frequency Division Multiplexing) [3] due to its great advantages such as spectral efficiency, robustness against multipath fading, among others. However, the OFDM signal occasionally has high power peaks, this problem is known as the PAPR problem (Peak-to-Average Power Ratio) [3]. When the OFDM signal with high peaks go through an HPA (High Power Amplifier), the signal suffers distortions that reduce the system efficiency [4]. There are several techniques for reducing PAPR, discussed widely in the literature (for more detail, refer to [5] and [6]), where each technique has different characteristics and computational complexity.

The OPS-SAP technique (Simple Amplitude Predistortion aided by Othogonal Pilot Sequences ) is one of the most promising for ad-hoc environments [3], [7] because of this technique not present distortions in the signal, so it doesn’t show degradations in the BER (Bit Error Rate). In addition, this technique doesn’t need the transmission of additional information to the receiver, therefore there isn´t loss of efficiency in the transmission speed.

To assess efficiency of a PAPR reduction technique different metrics are used such as: (1) CCDF (Complementary Cumulative Distribution Function), to determine the probability that the PAPR of a system is greater than or equal to certain threshold; (2) PSD (Power Spectral Density) determines the radiation inserted in the signal after passing through a HPA; (3) BER (Bit Error Rate) quantifies the BER required for a given SNR (Signal-to-Noise Ratio) y (4) PER (Packet Error Rate), is a parameter widely used by QoS (Quality of Service) in wireless networks . In [8] there are some simulations, which show that when the OPS-SAP technique is used in IEEE 802.11p, there is a gain in PER of approximately 0,5 dB in SNR at the same probability of 10^(-3).

In the literature there are many types of formulas for the PER which can be classified in analytical and empirical methods. Each of the different proposals to estimate the PER consider paremeters such as: number of lost packets, delay, hops, distance, SNR [9]. However, aspects by the PAPR don't have been included in any of the studies found in the literature. Consequently, the present project aims to determinate a new way to calculate the PER, wich includes the gain or loss due to the inclusion of PAPR techniques, especially the OPS-SAP.

1. Gerla, Mario, “Ad hoc networks”. In Ad Hoc Networks Technologies and Protocols. pp. 1-22. Springer US, 2005.
2. IEEE, IEEE Standard for Information technology- Local and metropolitan area networks - Specific requirements – Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 6: Wireless Access in Vehicular Environments, IEEE Std 802.11p-2010. (Amendment to IEEE Std 802.11-2007 as amended by IEEE Std. 802.11k-2008, IEEE Std 802.11r-2008, IEEE Std 802.11y-2008, IEEE Std 802.11n-2009, and IEEE Std 802.11w-2009. Year 2010. doi:10.1109/IEEESTD.2010.5514475.
3. M. C. Paredes Paredes, M. J. Fernández-Getino García, “Performance evaluation of OPS-SAP PAPR reduction technique in OFDM systems in a wireless vehicular context”, In Proceedings of the 12th ACM Symposium on Performance Evaluation of Wireless Ad Hoc, Sensor, & Ubiquitous Networks, ACM, 2015, pp. 49-54.Cancún – Mexico. doi:10.1145/2810379.2810392.
4. F. Danilo-Lemoine, D. Falconer, C.-T. Lam, M. Sabbaghian, K. Wesolowski, “Power backoff reduction techniques for generalized Multicarrier waveforms”, Journal on Wireless Communications and Networking, EURASIP 2008, pp. 437-80, DOI:10.1155/2008/437801.
5. T. Jiang, Y. Wu, An overview: Peak-to-Average power ratio reduction techniques for OFDM signals, IEEE Transaction on Broadcasting, Vol. 54, no. 2, 2008, pp. 257–268, doi: 10.1109/ 499 TBC.2008.915770 .
6. Y. Rahmatallah, S. Mohan, Peak-To-Average power ratio reduction in OFDM 501 Systems: a survey and taxonomy, IEEE Communication Survey Tutorial, vol. 15, no. 4, 2013, pp. 1567–502 1592, doi: 10.1109/SURV.2013.021313.00164 .
7. M. C. Paredes Paredes and M. J. Fernandez-Getino Garcia, "Energy efficient peak power reduction in OFDM with amplitude predistortion aided by orthogonal pilots", in IEEE Transactions on Consumer Electronics, vol. 59, no. 1, pp. 45-53, February 2013. doi: 10.1109/TCE.2013.6490240
8. M.C. Paredes, M. Julia Fernández-Getino García, Performance of OPS-SAP technique for PAPR reduction in IEEE 802.11p scenarios, Ad Hoc Networks (2016), http://dx.doi.org/10.1016/j.adhoc.2016.07.010
9. Tripp-Barba, C., Urquiza-Aguiar, L., Estrada, J., Aguilar-Calderón, J. A., Zaldívar-Colado, A., & Igartua, M. A. “Impact of packet error modeling in VANET simulations”. In 2014 IEEE 6th International Conference on Adaptive Science & Technology (ICAST), pp. 1-7. Ota, 2014, pp. 1-7.doi: 10.1109/ICASTECH.2014.7068133