Japan’s largest mobile operator by subscribers, NTT DOCOMO, today announced that in a joint trial conducted with MediaTek it has successfully developed a chipset to increase the spectral efficiency of mobile devices by up to 2.3 times compared to existing LTE technology. The press release confirms that the vendor’s chipset ‘combines DOCOMO’s non-orthogonal multiple access (NOMA) radio access technology and MediaTek’s multi-user interference cancellation (MUIC) technology, which is required to achieve NOMA. The radio access technology multiplexes signals at a base station transmitter to leverage the increased signal processing capacity of user devices and cancel interference among multiplexed user signals. MUIC removes interference from other users when a base station transmits a signal to several users simultaneously. The trial – which comprised three smartphone-sized devices embedded with the chipsets, each placed in a different location – resulted in up to 2.3 times greater spectral efficiency than that of single-user Multi Input Multi Output (MIMO).