The 3GPP has published a list of the specifications that its RAN working group will be working on for R14, due to be completed by June 2017.
Dino Flore, RAN Group Chairman said that the list gives a “good idea on how LTE will evolve to meet various market demands”.
R14 will be the second release that falls under the LTE-A Pro marker, and as such most of its RAN features are aimed at tweaking the efficiency or performance or optimisation of LTE networks.
This includes a bunch of things that the vendors may be able to include in their 4.5G or pre-5GH or “road to 5G” marketing, things like enhanced uplink and enhanced cell coordination, enhanced FD-MIMO, or “lighter” signalling. You can see that list, with links to the proposal documents, here.
There are other areas which are of note, however, in that they address specific use cases, and/or vertical markets.
LTE WiFi link Aggregation (LWA)
Falling into the use case bracket will be further enhancements to the 3GPP’s specifications for LTE in unlicensed spectrum – LWA and LAA. Getting LAA and LWA into R13 has been something of a rush, so necessarily some elements have been left until R14.
One of these is to enhance interworking between LTE and WLAN at the radio level. This has become more necessary because of the increasing speeds being built into WLAN 802.11x standards. One of those, 802.11ay, is an amendment that can offer data rates of up to 20Gbps in the 60GHz wave band. 3GPP said that such increased data rates “may require additional optimisations”. These would include supporting 60 GHz channel measurements, and increased data rates for 802.11ax, 802.11ad, and 802.11ay – for example by PDCP optimisations.
There are also objectives to gain additional information collection and feedback for better estimation of available WLAN capacity, and for the introduction of Automatic Neighbour Relations for LWA – for the discovery of WLANs that sit in eNodeB coverage.
Additionally, it looks likely that we will see more co-operation between IEEE and 3GPP on LWA operation – with IEEE 802.11 said to be willing to improve “802.11 as a component” within the 3GPP umbrella. That may allow LWA and 802.11 evolution to be “more harmonious”.
Licensed Assisted Access
On LAA there is a new study item and a new work item to complete work on defining an Uplink Access scheme. R13 defined the downlink channel access mechanism but stopped short of completing work on the uplink. The work item will support uplink carrier aggregation for LLA small cells, using the downlink access mechanisms as a starting point, with the aim of specifying the necessary device and base station performance requirements needed to support Uplink carrier aggregation for an LAA small cell.
Context Aware Service Delivery
The 3GPP will study context aware service delivery in the RAN for LTE. It says it doesn’t want to duplicate the work done by ETSI on Mobile Edge Computing, which it describes as being based around mobile video delivery optimisation and local caching. Instead it wants to study and identify any requirements for how the LTE radio network could acquire service specific information, could support RAN based local cached delivery and local breakout – and also how it could support RAN optimisations based on context awareness.
This really could mirror work being done within ETSI, and by ETSI’s MEC ISG members.
So what is it the 3GPP will be bringing to the table? Well, it says that there have been two main approaches to context-aware service delivery. One has been the Mobile Edge Computing initiative, as mentioned. The other has come from the app layer, such as via MPEG.
The 3GP proposal says that network-based proprietary solutions either require extensive DPI for user plane packets or a private interface to the content server. It wants to study whether UE assistance can enable more efficient cross-layer optimisation and caching. In addition, it says these existing solutions may be difficult for operators with multiple network vendors to deploy and operate.
In summary, there is a need for further study in the RAN to fill the gap between current LTE network capability and the diverse user service requirements of the future network. The work will be undertaken as a study item.
Device to Device
One of the vertical areas R14 will be looking at is Device to Device (D2D) and device-to-network relays for IoT and Wearables. This really means looking at how remote devices, like wearables, connect to other devices that in turn connect to the access network. An example might be a wearable device of some kind that relays back to the network via a connection to a smartphone.
Work on enabling Proximity Services started in R12 with the focus on Public Safety applications and continued in R13. The 3GPP proposal says there is a lot of interest in using LTE technology to connect and manage low cost MTC devices, such as wearables, “which also have the benefit of almost always being in close proximity to a smartphone that can serve as a relay”.
One study item is to give networks the ability to differentiate between traffic coming from a wearable and from the relay device (eg smartphone) in the access layer. Achieving that differentiation would allow the operator to treat the wearable or remote device as separate devices, say for billing or security. In particular, 3GPP security associations never reach end-to-end between the network and the remote device, meaning that the relay (smartphone) has clear text access to the remote device’s communications. 3GPP would like UE-to-Network relaying to be enhanced to support end-to-end security through the relay link, service continuity, E2E QoS where possible, efficient operation with multiple remote UEs, and efficient path switching between Uu and D2D air-interfaces.
(The item will also look at UE to relay access over non-3GPP access. e.g. Bluetooth, WiFi).
A second strand in the study item is to look at enhancements to give remote devices the ability to operate at lower power, rate and complexity. The idea is to reuse the ideas developed during NB-IoT and eMTC studies, e.g. the NB-IoT/eMTC uplink waveform can be reused for D2D. Such devices will potentially use a single modem for communicating with the Internet/cloud and for communicating with proximal devices. The current PC5 link design – the interface between devices – is inherited from the design driven by public safety use cases and represents a bottleneck that prevents low power and reliable D2D communication, due to lack of any link adaptation and feedback mechanisms. These shortcomings will not enable designers to achieve the required performance metrics for wearable and MTC use cases in terms of power consumption, spectrum efficiency, and device complexity.
Therefore R14 will see 3GPP look to study and define a generic UE-to-Network Relay architecture, including methods for the network to identify, address, and reach a remote UE via a relay UE.