According to International Telecommunication Union (ITU) Radio Communication Sector, the set of requirements for 5G in order to evaluate 5G solutions provided by 3GPP are listed as follows.
- Peak Date Rate: It is a theoretical figure because it represents peak throughput which can be achieved by a single user in ideal radio conditions considering there are no air interface error. Assumption in order to achieve this throughput is that a higher operating band is available.
- Spectrum Efficiency: It is measured as throughput per unit bandwidth. Using 8x8 MIMO spectral efficiency improvements can be achieved. In case of TDD, Spectral Efficiency calculations need to take into account uplink/down-link factor -- in other words the ratio between the uplink and downlink time slots on shared carrier. Peak spectral efficiency requirements are also theoretical because they assume ideal radio conditions and assume 8 spatial multiplexing streams in the downlink and 4 spatial multiplexing streams in the uplink
- User Experience Data Rate: It represents the throughput which can be achieved by 95 percent of the users within a dense urban coverage area. The major difference between peak data rate and user experienced data rate is the difference between ideal peak performance and more realistic performance which can be achieved by 95 percent of users. In case of small cell and indoor solutions experienced data rate will usually be higher.
- User Spectral efficiency: It represents spectral efficiency which can be achieved by 95 percent of the users within a specific coverage (indoor hotspot, urban etc.) In case of frequency re-use factor greater than 1, different calculations are used. In case of TDD, channel bandwidth is also scaled by uplink /downlink factor.
- Average spectral efficiency per Transmission/Reception (TRP): It represents the average spectral efficiency per unit of hardware. This metric also accounts for frequency re-use pattern and uplink/downlink factor.
- Area Traffic Capacity: total traffic throughput per mxm. It depends on site density. Higher site densities are expected to generate higher area traffic capacity (under ideal conditions). This area traffic capacity is only specified for the downlink in case of indoor scenario.
- User plane latency: represents contribution of the radio network towards the one-way delay associated with transferring an application packet. It is usually defined as the delay between a packet entering layer at the transmit side and leaving layer at the receive side. The assumption is that UE is already RRC connected and is ready to transfer data and small packet size. Special cases have different scenarios for latency requirements.
- Control Plane Latency: represents the delay associated with making the transition from a battery efficient (dormant or idle ) state to the start of continuous data transfer. In case of eMBB and URLLC there are separate requirements. According to ITU-R , target values less than 20 msec. In case of 4G the target value was 100 msec.
- Connection Density: represents maximum number of UE per unit area which allows those UE to fulfill a specific Quality of Service (QoS).
- Energy Efficiency : This requirement is applicable for both the device and the network. Energy efficiency in active state is reflected by the average spectral efficiency. Energy efficiency in inactive state is reflected by sleep ratio. Recommendation is to support high sleep ratio with a long sleep duration.
- Reliability: Ability to transmit a specific quanity of traffic within a specific time duration with a high probability of success. The success probability must be 99.999 percent when transferring 32 bytes of data within a 1 ms time duration.
- Mobility: corresponds to the ability to maintain a specific normalized traffic channel data rate while moving at a specific speed. It is calculated by dividing the data rate by the traffic channel bandwidth rather than complete bandwidth. ITU-R recommends specific uplink requirements for a range of environment types and speeds.
- Mobility Interruption Time: represents duration that a UE is unable to transfer any user plane packets when completing a handover. The requirement is applicable for both eMBB and URLLC use cases as well. Recommend value is 0 msec so data transfer must be continuous during mobility procedures.
The above requirements are recommended from ITU-R . In addition 3GPP has generated and recommended its own set of requirements as well for 5G which meet or exceed ITU-R requirements. These requirements are listed in 3GPP TR 38.913
- 3GPP recommends User plane latency of 0.5 msec for both uplink and downlink for URLLC use case.
- 3GPP has also specified a 10 msec Control Plane Latency.
- 3GPP TR 38.913 specifies that user plane latency can be as high as 600 msec for geostationary orbits, 180 msec for medium earth orbits and 50 msec for low earth orbits
References:
- 5G New Radio in Bullets by Chris Johnson
- ITU-R M.2410-0
- ITU-R M.2412-0
- 3GPP TR 38.913
- 3GPP TS 22.261