5 Facts about mmWave mobile radio
Millimetre-wave mobile communication is challenging due to harsh radio propagation conditions and severe hardware impairments that are experienced at extremely high carrier frequencies and large signal bandwidths. The research and development of novel radio access technologies at the mmWave frequency bands is one of the core tasks of mmMAGIC project.
The key technology facts of the mmWave radio interface are summarized below.
OFDM waveform was chosen due to its high spectral efficiency, flexibility, MIMO compatibility and low implementation complexity. OFDM waveform with flexible numerology (subcarrier spacing, cyclic-prefix) addresses wide range of frequencies and deployments, service latency and reliability requirements, user mobility, and hardware impairments.
2. Channel codes
LDPC codes were selected for high throughput and low latency data transmission. Polar codes were adopted for transmission of reliable control information. Moderate complexity channel decoders were developed for ultra-high throughput transmission.
3. Frame structure
A common frame structure for TDD and FDD that supports fast decoding of data via front loaded reference symbols, fast acknowledgements for retransmissions, integrated access and backhaul transmissions, transmission in both licensed and unlicensed spectrum, and slots of varying lengths for different types of services.
4. Reference signals
Beamformed reference signals for phase noise compensation, channel estimation for data demodulation, and channel state acquisition for MIMO transmission in both UL and DL. Reference signals are designed to optimize network energy efficiency.
5. Dynamic spectrum sharing
Network operators can reuse/share spectrum by exploiting separation in spatial domain (to reduce interference) via beamforming. Various spectrum sharing architectures (based on different level of coordination between RAN and core network) and supporting functions (spectrum sensing, enhanced CSI acquisition and exchange, synchronization, beam coordination) have been developed and evaluated, showing significant benefits of dynamic spectrum usage.
Source: Ericsson Research Blog0