Not all the innovations coming out of the mobile world relate to 5G or 4.5G. There is still plenty of usage of 2G and 3G networks round the world, and some spectrum-constrained operators face extreme challenges when it comes to boosting capacity and migrating users to mobile broadband. Huawei has applied a very advanced technique, spectrum overlapping – which could have significant implications for 4G and 5G spectral efficiency – to these older networks, supporting gradual migration from GSM to UMTS in only 5 MHz of bandwidth. The GU@5 MHz solution takes a new approach to spectrum refarming for those operators which do not have enough blocks in the 900 MHz band to support a dual-RAT 2G/3G system – about…