Implementation and Benchmarking of Hardware Accelerators for Ciphering in LTE Terminals

In this paper we investigate hardware implementations of ciphering algorithms, SNOW 3G and the Advanced Encryption Standard (AES), for the acceleration of the protocol stack layer 2 in the 3G Long Term Evolution (LTE). This analysis is based on timing requirements from execution time measurements in a simulated mobile phone platform, where we apply data rates of 100 Mbit/s and above (200 and 300 Mbit/s) to account for LTE and beyond LTE investigations. Different architectures for both algorithms are explored in order to meet the performance requirements, while keeping the power and area budget at a reasonable level. Therefore, a hardware analysis is done using a standard cell library of Faraday´s 90 nm CMOS technology. Finally, the cryptographic substitution box with one-hot encoding emerges as the best solution for both ciphering schemes. Additionally, the 128-bit data path in the AES is identified as the most suitable architecture for LTE terminals, whereas a dual-AES approach turns out to be a candidate for data rates far beyond LTE (like LTE-Advanced).