Several contributors to the emerging 5G standard presented last week at the 15th annual Texas Wireless Summit at the University of Texas, hosted by the school’s Wireless Networking and Communications Group.
Qualcomm’s Sundar Subramanian, who is leading the company’s millimeter-wave and 5G standardization effort, spoke about integrating millimeter wave and sub-6 GHz frequency bands. He said Qualcomm foresees operators using the sub 6 GHz bands for coverage and the millimeter wave bands for capacity.
Subramanian said there are four conditions that must be satisfied in tests in order to show that millimeter wave is viable for long-term commercial deployments. First, the technology must support sustained outdoor mobile communication, enabling mobility without line of sight. Second, it must show sustained connectivity indoors, be able to penetrate walls, and use beamforming to navigate around bodies. Third, it must demonstrate this coverage when antennas and radios are co-located with existing LTE sites. And finally, the 5G user equipment must work with the network infrastructure. Subramanian said Qualcomm is seeing progress in all these areas, and has a 5G New Radio millimeter wave RF front-end prototype. He said Qualcomm is planning to commercialize millimeter wave RF front ends in 2019.
Zukang Shen, senior expert for 5G New Radio at Huawei, is also involved in the 5G standardization process. He said signaling overhead can be cut by 81% through a process known as “grant free transmissions.”
“In LTE, if a user device has data to transmit it will send a scheduling request and the eNodeB will send a ‘scheduling granted’ and the data will be transmitted,” Shen explained. 5G NR, he said will use “grant=free” transmission for sporadic, small packet transmissions. “This has the benefit of low-latency signaling overhead,” he said.
Shen also said that a new user equipment status will be part of 5G – inactive data status. This is between active and inactive in that the device is not trying to connect to the network, but if data is sent to the device it can transmit immediately.
In addition, Shen predicted that 5G devices will be capable of multiuser detection. Multiuser detection means that data signals from all users are detected by the receiver and are not treated as interference. Shen said Huawei already has prototypes for these devices.