Content for  TS 22.261  Word version:  19.1.0

The increased density of access nodes needed to meet future performance objectives poses considerable challenges in deployment and management (e.g. backhaul availability, backhaul capacity and scalability). The use of wireless backhaul for such access nodes helps to address some of the challenges. Wireless self-backhauling in the radio access network can enable simpler deployment and incremental rollout by reducing reliance on the availability of wired backhaul at each access node location. Network planning and installation efforts can be reduced by leveraging plug and play type features -- self-configuration, self-organizing, and self-optimization.

The 5G network shall enable operators to support wireless self-backhaul using NR and E-UTRA. The 5G network shall support flexible and efficient wireless self-backhaul for both indoor and outdoor scenarios. The 5G network shall support flexible partitioning of radio resources between access and backhaul functions. The 5G network shall support autonomous configuration of access and wireless self-backhaul functions. The 5G network shall support multi-hop wireless self-backhauling. The 5G network shall support autonomous adaptation on wireless self-backhaul network topologies to minimize service disruptions. The 5G network shall support topologically redundant connectivity on the wireless self-backhaul.

The proliferation of video services, ad-hoc multicast/broadcast streams, software delivery over wireless, group communications and broadcast/multicast IoT applications have created a need for a flexible and dynamic allocation of radio resources between unicast and multicast services within the network as well as support for a stand-alone deployment of multicast/broadcast network. Moreover, enabling such a service over a network for a wide range of inter-site distances between the radio base stations will enable a more efficient and effective delivery system for real-time and streaming multicast/broadcast content over wide geographic areas as well as in specific geographic areas spanning a limited number of base stations. A flexible multicast/broadcast service will allow the 5G system to efficiently deliver such services.

The following set of requirements complement the requirements listed in TS 22.146, TS 22.246 and TS 22.101, clause 32. The 5G system shall support operation of downlink only broadcast/multicast over a specific geographic area (e.g. a cell sector, a cell or a group of cells). The 5G system shall support operation of a downlink only broadcast/multicast system over a wide geographic area in a spectrally efficient manner for stationary and mobile UEs. The 5G system shall enable the operator to reserve 0% to 100% of radio resources of one or more radio carriers for the delivery of broadcast/multicast content. The 5G network shall allow the UE to receive content via a broadcast/multicast radio carrier while a concurrent data session is ongoing over another radio carrier. The 5G system shall be able to support broadcast/multicast of UHD streaming video (e.g. 4K/8K UHD). The 5G network shall allow the operator to configure and broadcast multiple quality levels (i.e. video resolutions) of broadcast/multicast content for the same user service in a stand-alone 3GPP based broadcast/multicast system. The 5G network shall support parallel transfer of multiple quality levels (i.e. video resolutions) of broadcast/multicast content for the same user service to the same UE taking into account e.g. UE capability, radio characteristics, application information. The 5G system shall support parallel transfer of multiple multicast/broadcast user services to a UE. The 5G system shall support a stand-alone multicast/broadcast network comprising of multiple cells with inter-site distances of up to 200 km. The 5G system shall support multicast/broadcast via a 5G satellite access network, or via a combination of a 5G satellite access network and other 5G access networks. The 5G system shall support interworking of 5G multicast/broadcast with non-3GPP digital terrestrial broadcast networks. The 5G system shall be able to setup or modify a broadcast/multicast service area within [1s]. The 5G system shall be able to apply QoS, priority and pre-emption to a broadcast/multicast service area. The 5G system shall support downlink parallel transfer of the same content, via broadcast/multicast and/or unicast, such that all receiver group members in a given area receive the media at the same time according to user perception. The 5G system shall support a mechanism to inform a media source of relevant changes in conditions in the system (e.g. capacity, failures). The 5G system shall provide means for a media source to provide QoS requirement requests to the broadcast/multicast service. The 5G system shall provide means for the broadcast/multicast service to inform the media source of the available QoS, including modification of available QoS characteristics and availability of the broadcast/multicast service. The 5G system shall be able to support broadcast/multicast of voice, data and video group communication, allowing at least 800 concurrently operating groups per geographic area. The 5G system shall support delivery of the same UE-originated data in a resource-efficient manner in terms of service bit rate to UEs distributed over a large geographical area. The 5G system shall allow a UE to request a communication service to simultaneously send data to different groups of UEs at the same time. The 5G system shall allow different QoS policy for each group the UE communicates with.

With the Internet of Things, it is expected that the diversity of IoT devices (e.g. sensors, UAVs, smart flower pots) and the usage models will largely vary. Moreover, when the IoT device is manufactured, the deployment location and specific usage might not be known. Sometimes the IoT devices will be added to existing subscriptions, other times they can be part of a new subscription for the user. Sometimes the IoT devices can be leased. During their life cycle these IoT devices go through different stages, involving the change in ownership when the IoT device is deployed and possibly afterwards, the activation of the IoT device by the preferred operator, a possible change of operators, etc. These stages need to be managed securely and efficiently. A method of dynamic subscription generation and management is needed in addition to statically provisioned subscription. Once the subscription is established, subscription management becomes necessary, for example, to modify the subscription when the ownership of the IoT device changes, to update or refresh credentials due to suspected leakage or theft of security keys or as a preventive measure. The Internet of Things will also support various connectivity models: The IoT devices can connect with the network directly or connect with the network using another IoT device as a relay UE, or they can be capable of using both types of connections. The direct device connection between the IoT device and the relay UE can be using 3GPP or non-3GPP RAT. The relay UE can access the network also using 3GPP or non-3GPP access networks (e.g. WLAN, fixed broadband access network). In order to identify and manage the IoT devices, a subscription with the 5G network is needed, even if the access is done via non-3GPP access.

An IoT device which is able to access a 5G PLMN in direct network connection mode using a 3GPP RAT shall have a 3GPP subscription. The 5G system shall allow the operator to identify a UE as an IoT device based on UE characteristics (e.g. identified by an equipment identifier or a range of equipment identifiers) or subscription or the combination of both. The 5G system shall be able to provide mechanisms to change the association between a subscription and address/number of an IoT device (e.g. changing the owner and subscription information associated with the IoT device) within the same operator and in between different operators in an automated or manual way. The 5G system shall be able to support identification of subscriptions independently of identification of IoT devices. Both identities shall be secure. An IoT device which is able to connect to a UE in direct device connection mode shall have a 3GPP subscription, if the IoT device needs to be identifiable by the core network (e.g. for IoT device management purposes or to use indirect network connection mode). Based on operator policy, the 5G system shall support a mechanism to provision on-demand connectivity (e.g. IP connectivity for remote provisioning). This on-demand mechanism should enable means for a user to request on-the-spot network connectivity while providing operators with identification and security tools for the provided connectivity. The 5G system shall support a secure mechanism for a home operator to remotely provision the 3GPP credentials of a uniquely identifiable and verifiably secure IoT device. The 5G system shall support a secure mechanism for the network operator of an NPN to remotely provision the non-3GPP identities and credentials of a uniquely identifiable and verifiably secure IoT device. Based on MNO and NPN policy, the 5G system shall support a mechanism to enable MNO to update the subscription of an authorized UE in order to allow the UE to connect to a desired NPN. This on-demand mechanism should enable means for a user to request on-the-spot network connectivity which is authorized by its MNO. Based on operator policy, the 5G system shall provide means for authorised 3rd parties to request changes to UE subscription parameters for access to data networks, e.g., static IP address and configuration parameters for data network access.

Energy efficiency is a critical issue in 5G. The potential to deploy systems in areas without a reliable energy source requires new methods of managing energy consumption not only in the UEs but throughout all components of the 5G system. Small form factor UEs also typically have a small battery and this not only puts constrains on general power optimization but also on how the energy is consumed. With smaller batteries it is more important to understand and follow the limitations for the both the maximum peak and continuous current drain.

The 5G access network shall support an energy saving mode with the following characteristics:

• the energy saving mode can be activated/deactivated either manually or automatically;
• service can be restricted to a group of users (e.g. public safety user, emergency callers).

The 5G system shall support mechanisms to improve battery life for a UE over what is possible in EPS. The 5G system shall optimize the battery consumption of a relay UE via which a UE is in indirect network connection mode. The 5G system shall support UEs using small rechargeable and single coin cell batteries (e.g. considering impact on maximum pulse and continuous current).

A key aspect of 5G system flexibility is the ability to support both the very high-end markets as well as very low end markets. Some systems will be deployed in areas where there are constraints on energy resources (e.g. sporadic access to power) and lower end user expectations for availability, reliability, and data rates. In such cases, the system needs additional flexibility to adapt power consumption needs based on fluctuations in power availability. The system should be efficient in order to provide essential services in harsh environments (e.g. far remote rural areas, very large territories) while taking into account the local constraints (adapting resources consumptions to long distances, dealing with variable conditions and possibly disconnections). Content delivery should be optimized in order to reduce constraints on transport networks, on low-end UEs (e.g. small screen, limited energy consumption), variable network conditions, and client profiles.

In constrained circumstances (e.g. reduced power supply), the 5G system shall be able to support a minimal user experience (e.g. user experienced data rate of [100] kbit/s, E2E latency of 50 ms, lower availability of the network of 95%). The 5G system shall support centralized automation and management of the network in order to reduce local management tasks. The 5G system shall support a mechanism to reduce data transfer rate at the cell edge for very large coverage area (e.g. 100 kbit/s for more than 100 km cell coverage, 1 Mbit/s for 100 km cell coverage). The 5G system shall be able to give priority to services (e.g. e-Health) when resources are limited.

A fully connected society is expected in the near future. The network access everywhere over long distances (e.g. at remote rural areas or at sea) including both humans and machines need to be supported.

The 5G system shall support the extreme long-range coverage (up to 100 km) in low density areas (up to 2 user/km2). The 5G system shall support a minimum user throughput of 1 Mbit/s on DL and 100 kbit/s on UL at the edge of coverage. The 5G system shall support a minimum cell throughput capacity of 10 Mbit/s/cell on DL (based on an assumption of 1 GB/month/sub). The 5G system shall support a maximum of [400] ms E2E latency for voice services at the edge of coverage.

Given the multitude of use cases for new verticals and services, each operator, based on its business model, can deploy a network serving only a subset of the vertical industries and services. However, this should not prevent an end-user from accessing all new services and capabilities that will be accessible via 5G systems. To provide a better user experience for their subscribers with UEs capable of simultaneous network access, network operators could contemplate a variety of sharing business models and partnership with other network and service providers to enable its subscribers to access all services via multiple networks simultaneously, and with minimum interruption when moving.

The 5G system shall enable users to obtain services from more than one network simultaneously on an on-demand basis. For a user with a single operator subscription, the use of multiple serving networks operated by different operators shall be under the control of the home operator. When a service is offered by multiple operators, the 5G system shall be able to maintain service continuity with minimum service interruption when the serving network is changed to a different serving network operated by a different operator. In the event of the same service being offered by multiple operators, unless directed by the home operator's network, the UE shall be prioritized to receive subscribed services from the home operator's network.

The 5G system will support the concept of "network slices" where different NG-RANs potentially are connected to network slices of different SSTs. A 5G UE can provide assistance information (e.g. SST) to enable the network to select one or more network slices. A 5G system is foreseen to support one or more SSTs, but possibly not all existing SSTs. A 5G network operator controls and is responsible for what SSTs that should be available to a specific UE and subscription combination, based on associated subscription type, network operator policies, network capabilities and UE capabilities. The network operator can populate the Operator Controlled PLMN Selector list with associated access technology identifiers, stored in the 5G UE, with the PLMN/RAT combinations enabling access to the SSTs that are available to the 5G UE with associated subscription. The UE uses the list of PLMN/RAT combinations for PLMN selection, if available, typically during roaming situations. In non-roaming situations, the UE and subscription combination typically matches the HPLMN/EHPLMN capabilities and policies, from a SST perspective. That is, a 5G UE accessing its HPLMN/EHPLMN should be able to access SSTs according to UE capabilities and the related subscription. Optionally, a 5G system supports, subject to operator policies, a User Controlled PLMN Selector list that enables the 5G UE user to specify preferred PLMNs with associated access technology identifier in priority order. The user can obtain information about suitable PLMN/RAT combination that would support services preferred by the user.

The following set of requirements complement the requirements listed in TS 22.011, clause 3.2. The 5G system shall support selection among any available PLMN/RAT combinations, identified through their respective PLMN identifier and Radio Access Technology identifier, in a prioritised order. The priority order may, subject to operator policies, be provisioned in an Operator Controlled PLMN Selector lists with associated RAT identifiers, stored in the 5G UE. The 5G system shall support, subject to operator policies, a User Controlled PLMN Selector list stored in the 5G UE, allowing the UE user to specify preferred PLMNs with associated RAT identifier in priority order.

The 3GPP system is expected to support various enhanced V2X scenarios. Vehicles Platooning enables the vehicles to dynamically form a group travelling together. All the vehicles in the platoon receive periodic data from the leading vehicle, in order to carry on platoon operations. This information allows the distance between vehicles to become extremely small, i.e. the gap distance translated to time can be very low (sub second). Platooning applications can allow the vehicles following to be autonomously driven. Advanced Driving enables semi-automated or fully-automated driving. Longer inter-vehicle distance is assumed. Each vehicle and/or RSU shares data obtained from its local sensors with vehicles in proximity, thus allowing vehicles to coordinate their trajectories or manoeuvres. In addition, each vehicle shares its driving intention with vehicles in proximity. The benefits of this use case group are safer traveling, collision avoidance, and improved traffic efficiency. Extended Sensors enables the exchange of raw or processed data gathered through local sensors or live video data among vehicles, Road Site Units, UEs of pedestrians and V2X application servers. The vehicles can enhance the perception of their environment beyond what their own sensors can detect and have a more holistic view of the local situation. Remote Driving enables a remote driver or a V2X application to operate a remote vehicle for those passengers who cannot drive themselves or a remote vehicle located in dangerous environments. For a case where variation is limited and routes are predictable, such as public transportation, driving based on cloud computing can be used. In addition, access to cloud-based back-end service platform can be considered for this use case group.

The 3GPP system supports the transport of messages with different performance requirements to support V2X scenarios. The associated requirements are described in eV2X TS 22.186.

The increased density of access nodes needed to meet future performance objectives poses considerable challenges in deployment and acquiring spectrum and antenna locations. RAN sharing is seen as a technical solution to these issues.

Requirements related to NG-RAN sharing are described in TS 22.101, clause 28.2. A 5G satellite access network shall support NG-RAN sharing.