Build the Fastest 2G Modem Ever
The 2G cellular standard GSM and its packet data enhancements (GPRS and EDGE) is by far the most widely deployed cellular standard in human history and is still being actively deployed today. Despite the advancement of 4G networks many regions of the planet have only 2G coverage. As GPRS and EDGE provide rather low-throughput data connections (86 kbit and 238 kbit, respectively, using multislot class 12 or 4 timeslots), more advanced packet data enhancements such as Evolved EDGE  provide significantly higher throughput. The latter is achieved by using higher order modulation schemes, turbo codes, more timeslots, and 2 receive antennas. A throughput of 0.6 Mbit (1 antenna) and 1.2 Mbit (2 antennas), using multislot class 45 or 6 timeslots, can be achieved with the so called Level A flavor of Evolved EDGE. The Level B flavor uses a higher symbol rate and can achieve a throughput of 0.7 and 1.4 Mbit with 1 and 2 receive antennas, respectively. (By using 8 timeslots, which is the maximum, a throughput of 1.9 Mbit is achievable with 2 antennas). Current research at the institute led to a prototype of a modem RF-SoC in autumn 2016 as an enhancement to the stoneEDGE project. The SoC includes RF circuitry and a digital baseband ASIC for 2G EC-GSM-IoT, GSM, GPRS, EDGE, and Evolved EDGE Level A single-carrier multislot class 45 operations. However, support for Evolved EDGE Level B is still pending.
The goal of this project is to enhance the existing stoneEDGE solution with Evolved EDGE Level B. A Matlab framework will be provided. While no adaptions are required in the analog domain, the digital signal processing needs to be enhanced along the entire receive chain to cope with the higher symbol rate of Evolved EDGE Level B. If desired the outcome can be implemented in HDL and tested on an FPGA-based testbed using the evalEDGE FMC module with an Evolved EDGE base-station. This project is a perfect opportunity to get an insight on various stages of a digital receiver and provides hands-on experience with a fully integrated cellular modem.
- Contact: Benjamin Weber