Page 133 - ITU-T Focus Group IMT-2020 Deliverables

ITU-T Focus Group IMT-2020 Deliverables 3

RRH
RRH
RRH
5G-Xhaul Wireless 60GHz /Sub-6 links for FH/BH
Backhaul/Fronthaul RRH RRH
FH
eNB vBBU 1 vBBU 2 BH
eNB Fronthaul
RRH
WDM-PON vBBU 1
RRH vBBU 2
Small Macro TSON vBBU
Cells RRH Cell
VM
HeNB GW Data Centers
WLAN GW Backhaul vBBU
WiFi HeNB HeNB P-S GW/GSN
Femto vBBU EPC
Cells vBBU
HeNB Internet
VM
PDN-GW
Wireless Access
Figure 6.4.3-6 – 5G-XHaul network deployment

6.4.3.2 Development Focus and Research Challenges of 5G-XHaul
In the wireless domain, 5G-XHaul leverages on the SDN controlled mm-wave/Sub-6 GHz wireless transport.
While the state-of-the-art wireless transport solutions reach multi Gpbs data rates with ranges of up to 1 km,
they are typically realized using relatively expensive technologies. In this context, new mm-wave antenna
arrays and beamforming chipsets based on vector modulators will be developed, enabling flexible, robust,
and low cost point to multipoint (P2PM) wireless backhauling (BH) and fronthauling (FH) for an ultra-dense
network of small cells.
The innovations in the optical transport technology include further developments of the TSON concept with
protocol convergence through Ethernet access, very granular bandwidth allocation through a TDM
frame/flexigrid. On the other hand, WDM-PON will provide increased data rates up to 25+ Gbps, and an SDN
controlled interface.
Finally, 5G-XHaul brings together a heterogeneous set of wireless and optical transport technologies under a
logically centralised control plane following the SDN architecture. In particular, the 5G-XHaul control plane
will allow the users of the 5G-XHaul transport system to define transport slices specifying how a set of
distributed physical or virtual functions are connected through the 5G-XHaul infrastructure. In addition, the
5G-XHaul control plane features a North Bound Interface (NBI) that allows the tenants (in other words, users
of the 5G-XHaul transport system, which receive connectivity services over the transport network such as,
e.g. virtual 5G network operators) to independently control the functions in their transport slice.
6.4.3.3 5G-XHaul PoC

The most promising technologies in 5G-XHaul will be evaluated using three testbeds:
– The NITOS wireless testbed at the University of Thessaly, Greece, will generate realistic small cell
topologies and test SDN control elements.
– The TSON testbed at the University of Bristol, UK, will validate TSON aggregation and core network
topologies, and test the TSON SDN control elements.

– Finally, the developed components will be integrated in a city wide wireless-optical testbed in
Bristol, UK to validate the end-to-end solution mimicking a real-world scenario (cf. Figure 6.4.3-7).

127