scope:

The present document is aiming at the definition of new KPI's for planning microwave and millimetre wave backhaul networks. Identification of new KPI's should take into account the evolution of wireless backhaul:

• more challenging requirements coming from 5G deployment;

• new technologies aiming at more efficient interference mitigation and cancellation;

• increase of use of spectrum in the millimetre wave range, both stand-alone and aggregated (BCA);

• different typologies and mix of services transported.

User Experience is the key driver for backhaul dimensioning considered in the present document. Studies, carried out to produce the present document, have considered RAN traffic characteristics (both network measures and full (propagation, interference, multi users, scheduling and protocols) RAN simulations) in conjunction with backhaul link behaviour against propagation related fading (e.g. rain fading, multipath fading, etc.), with the aim to reach the most efficient backhaul spectrum usage and reduced Total Cost of Ownership (TCO).

The present document focuses primarily on "single backhaul link" (carrying one or multiple RAN site(s) traffic) that is baseline for MW/mmW planning. A few preliminary considerations on link daisy chains (legacy MW topology), hubs & spoke (on-going topology trend due to increasing fibre penetration) and more general geographic area approaches (i.e. clusters of hubs) can be found in annex A.

The present document considers RAN downlink traffic since it is more demanding than uplink traffic, thus becoming the backhaul link dimensioning constraint in case of FDD symmetric spectrum resources allocation (standard approach for all MW and mmW bands used for mobile backhaul today).

The present document is considering links already deployed and links that will be deployed using consolidated MW/mmW technology (such as ACM and BCA). However in the present document the reader will also find some general considerations on emerging MW/mmW technology evolutions.

The present document also provides an analysis of impacts and dependencies of the new KPI's on:

• network planning and monitoring (across entire link life cycle in a network);

• equipment standards (to spot if there are impacts or dependencies);

• spectrum regulations and licensing (to spot if there are impacts or dependencies).

Finally, it is also worth mentioning that Fronthaul (definition in 3GPP TR 38.801 [i.4]) is out of the present document scope, while mid-haul can be considered included in the scope of the present document because it has capacity & latency requirements very similar with backhaul ones. Regarding backhaul link, the present document focus is on propagation related fading and it does not consider end users experience impacts due to any other backhaul link impairments such as equipment failures, energy outage and network operations.