According to the chinese company ZTE, it seems that right now is possible that LTE-enabled smartphones to benefit of a 5G-like service without changing the air interface standards. These phones reference codes such as CSI-RS (channel state information reference signal) can be modified to support a lot of antenna ports.
Also, the phone needs to be modified for the feedback of hundreds of PMIs (Pre-coding Matrix Indicator).Yet, we find out that in TDD (time division duplex) mode, the symmetry of uplink and downlink channels can be used for channel estimation. Without feedback channels, the accuracy of channel estimation will exceed the feedback result.
The company invested in 4G vector processing chipsets development, chips that have extensible software architecture and can support pre-5G requirements just with a modified software and without chaning the hardware. Dr. Xiang Jiying said: “With next-generation 5g technologies being deployed in 2020, there were industry concerns over what technologies will be used in the next six years. To address this, ZTE proposes to apply some of the 5G technology on top of 4G to meet users’ requirements.”