Connecting the urban metropolis with
self-organising MP2MP wireless backhaul
Eric Wilson, Head of Business Development
Cambridge Wireless Small Cell SIG
24 September 2015
2
Metnet solution overview
• Fully self-organising
• Multipoint-to-multipoint
• No frequency planning
• No antenna alignment
• Simple installation
• Small form factor
• High capacity, low latency
• Very low CAPEX and OPEX
3
The world’s first self-organising
small cell microwave backhaul
• Up to 16 links per node
• Hybrid deployment
– Mesh
– Point-to-multipoint
– Point-to-point
• Fully self-organising
– Self-healing
– Interference aware
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Self-organising small cell backhaul
2 fibre sites, 22 Metnet nodes99 possible links
20 active traffic links with S-TDMA
China South Africa UKUSA
Growing deployment experience
• Frequencies: 26 and 28GHz
• Latency: Min 40μs, average 150μs
• Capacity (112MHz channel)
– Single node: 480 Mbps
– Dual node: 960 Mbps
– Single node >1 Gbps (GA 2016)
• Synchronisation
– GPS-derived, SyncE, 1588v2 (TC, BC)
– Can pass sync timing to local device
Node features and performance
7
Urban outdoor small cell backhaul
Macro cell Metnet HG node
Fibre PoPMetnet node
Small cell
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Smart cities
Macro cell Metnet HG node
Fibre PoPMetnet node
Small cell
Traffic
sensor
Surveillance
camera
Public WiFi
access point
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Internet
Enterprise/indoor small cell backhaul
Indoor
small cells
WiFi
access point
Metnet node
on rooftop
Ethernet
switch
Wireless
devices
Wired
devices
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AND NOW……urban outdoor C-RAN fronthaul!
Macro cell Metnet HG node
Fibre PoPMetnet node
C-RAN RRH
C-RAN
baseband pool
11
Evolution to HetNets
• Multi-layered mix of radio access technologies
• Different frequency bands
• Licensed/unlicensed spectrum
• Complex challenge of managing integration
• May be best supported through split RAN architecture with
centralised and distributed elements
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PHYMAC
RF
RRH
PNF
Services
VNF
S1/X2
SON
OAM
APPS
RRC
PDCPRLC
Upper
MACLower
MAC
Upper
PHY
Lower
PHY
PNF
PNF
PNF
PNF
PNF
Conventional distributed eNB
PDCP/RLC based VNF
RLC/MAC based decomposition
Split MAC based decomposition
MAC/PHY based decomposition
Split PHY based decomposition
Baseline macro: CPRI decomposition
Source: Small Cell Forum
Possible LTE base station decompositions Metnet supports Small Cell Forum’s MAC/PHY split
Metnet meets
requirements
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Fronthaul transport options
Use case One-way latency DL bandwidth UL bandwidth
PDCP-RLC Non-ideal – 30ms 151Mbps 48Mbps
RLC-MAC Sub-ideal – 6ms 151Mbps 48Mbps
Split MAC Sub ideal – 6ms 151Mbps 49Mbps
MAC-PHY Ideal – 250μs; Near ideal – 2ms 152Mbps 49Mbps
PHY Split I Ideal – 250μs; Near ideal – 2ms 173Mbps 452Mbps
PHY Split II Ideal – 250μs; Near ideal – 2ms 933Mbps 903Mbps
PHY Split III Ideal – 250μs; Near ideal – 2ms 1075Mbps 922Mbps
PHY Split IIIb Ideal – 250μs; Near ideal – 2ms 1966Mbps 1966Mbps
PHY Split IV Ideal – 250μs 2457.6Mbps 2457.6Mbps
Source: Small Cell Forum
Metnet meets
requirements
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Metnet fronthaul trial
• C-RAN vendor tested Metnet as
fronthaul to provide LTE service
• 4 Metnet nodes tested with 2 RRHs
• Rooftop and street-level installations
• Approx 50 metres apart in LOS
conditions
• Topologies tested: PTP, PTMP, relay
RRH locations
Alternative LOS routes
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Metnet fronthaul trial results
• No impact to performance for capacity, packet delay, latency and jitter
• Meets C-RAN vendor’s KPIs for fronthaul transmission
• Further testing planned
Vendor’s fronthaul requirements CCS Metnet
Latency 10’s of milliseconds Passed
Bandwidth 110Mbps Exceeded
BER <10-6 Passed
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Does C-RAN mean the end for small cells?
• Defer architecture question to RAN experts
• From transmission perspective:
– Similar challenges for fronthaul as backhaul
– How to connect remote equipment to the core?
– Transmission must be high capacity, low cost, resilient, plug & play,
adaptable, easy to scale…
– Flexible, self-organising and self-healing is most effective
• Pragmatic C-RAN architecture split (per SCF recommendation)
makes microwave-based links feasible
• Recommend adoption of SCF proposal for more flexible options to
connect RRH to core network