5G, as well as previous generations of cellular communication, relies on standardized communication protocols for the interactions between mobile terminal and the base station. With new and evolved features, and support of higher data rates, the complexity of the standards has increased for each new generation of mobile communication. 

Previous generations of cellular communication standards are using frequencies up to about 3 GHz, for which reliable communication can be maintained using one or a few omnidirectional antennas on the terminal side. With the introduction of NR frequency range 2 (24-71 GHz) (FR2), also known as mmWave, this is about to change as the radio propagation path loss at higher frequencies calls for beamforming based on multiple antenna elements to achieve sufficient sensitivity on both transmitter and receiver sides.

At a first glance it may seem that the requirements for beamforming in NR FR2 would only affect the radio front-end parts of the modem in a handheld device or the radio units in the base station, and by that only the radio frequency requirements of the 3GPP specifications. However, basically all aspects of the communication protocol for NR are affected when introducing mmWave communication.

The figure below shows a block scheme over the cellular modem part in a multi-RAT 5G-NR smartphone, supporting all communication generations from 2G to 5G.  The modem can be partitioned into (1) radio components supporting the sub 6 GHz communication (i.e. all legacy communication 2G-4G and also the sub 6 GHz communication mode (FR1) in 5G), (2) radio components supporting the mmWave communication introduced in 5G-NR, and (3) a baseband processor performing all algorithms needed to process a received radio signal to an information signal in the receiver and generate a radio signal from the transmitted information signal in the transmitter. The figure also shows which parts of the radio blocks and baseband processor algorithms that need to be updated for mmWave communication, such as (with reference to respective 3GPP standardization document number)

  • Radio frequency requirements (38.101-2)
  • Demodulation performance requirements (38.101-4)
  • Radio resource management (38.133)
  • Physical channels and modulation (38.211)
  • Physical layer procedures for control and data (38.213, 38.214)
  • Physical layer measurements (38.215)
  • Media access control (38.321)
  • Radio resource control (38.331) 

As can be seen mmWave communication is not only about radio design but it affects basically all algorithms and procedures in the modem, from the physical layer, up to the RRC layer .

Figure: a block scheme of a modem in a handheld device and corresponding parts affected by mmWave communication.

BeammWave understands all these aspects of the standard and how mmWave will impact the system design in handheld and fixed wireless devices, as well as in base stations, and will deliver a sustainable, scalable digital beamforming solution that enables the mass market for mmWave communication for 5G-NR.

Posted by Joakim Axmon

Systems expert with +600 granted patents, with extensive experience from 3GPP

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