small cell interoperability in the ran

Small Cell Interoperability in the RANImpossible Physics, Hard Design, or just Red-Tape?

V2.3, 1st October 2014

CTO

N.D. Johnson

(C) 2014 ip.access Ltd All rights reserved

Small Cell Interoperability

Why do we care?

• Some anecdotes from history

• Abis, Iu-b, Iu-r

Beyond standards

• NGMN, SCF and other interoperability initiatives

Buridan Telecom

• In the end, you have to choose

The schizophrenic vendor

• Can you be the incumbent and the upstart at the same time?

Interoperability and cloud-RAN

• Don’t be beguiled into another layer of private interfaces

A message of hope

• It might just work!


A traditional multi-vendor RAN deployment

3

A traditional multi-vendor

RAN deployment divides the

network into regions.

A “traditional” residential

femto deployment has no

such regionality.

Already we have a multi-

vendor RAN, and it’s no niche.


A new generation of problems – inter-layer multi-vendor IOT for handover

4

Where multi-

vendor IOT used

to be a line

across a country,

now It’s possible

at every

handover


Laws-of-physics : Where are the issues?

Load balancing:

• Reselection and Handover

• both directions

• 3G and LTE

Interference Management

• Pilot/FACH power tuning

• Avoidance and

coordination

• Open and Closed mode

Synchronisation

• Frequency synch

• Time/frame synch

Solved? Relies On

Standard signalling

R9 CSG + delta-SFN, MLB

CCO, ICIC, eICIC, CSG

PTP/NTP transport

Off-channel NWL

…the physics is not impossible


Small Cell Forum Plugfests summary

TopicsTaking

Part

Test

casesVenue

3G (1)

March 2010IPSec,

Iuh interface22 26

Sophia Antipolis,

France

3G (2)

Jan 2011HMS (TR-069) interface 14 35

Sophia Antipolis,

France

3G (3)

June 2011Mobility scenarios 12 42 Lannion, France

LTE (1)

June 2013S1, X2, Mobility scenarios,

VoLTE20 28 Kranj, Slovenia

LTE (2)

June/July 2014

Regression:

• S1, X2, Mobility, VoLTE,

New

• HEMS, CMAS, CSFB, SON (ANR,

PCI, MRO)

25 94 Paris, France

3G participation

diminishes as the

problems

disappear

LTE participation

still growing as

the problems are

addressed


But even here, the interoperability problems lurk

TR196 v2.0.1 is not backwards compatible with TR196 v.2.0.0

• WTF?

SCF and NGMN studies have shown key procedures in X2 are non-interoperable

X

X

? ?

X


How has it come to be like this?

GSM A-bis interoperability:

• Late 90s, attempts to interoperate vendor E BSC with vendor P BTS fail

• Largely due to management model incompatibility

Early noughties, Radioframe succeeds in interoperating E// and NSN A-bis

• 2009, Radioframe stops trading

ip.access tries to interoperate with 3rd party IP-BSCs

• Just in time for the telecom winter

• Pivots in 2001/2 to create a full RAN solution

2001, Kevab creates innovative node-B, with Iu-b to NSN and other RNCs

• 2003, Andrew Corp acquire Kevab, then 3GNS acquire the tech in 2009, now?

The lesson is:

• working to non-interoperable interfaces through incumbent proprietary gateways is business suicide


The scale of the problem – how big are these interfaces?

0

200

400

600

800

1000

1200

1400

1600

Abis+Gb Iu-b Iu-h LTE

Basestation to Controller lines of spec.

0

200

400

600

800

1000

1200

1400

GSM Iu-r Iu-rh X2

Cell to Cell lines of spec.

0

500

1000

1500

2000

2500

2G 3G 3G femto 4G

Radio Resource Control (RRC)

lines of spec.

0

50

100

150

200

250

300

350

400

450

500

2G 3G 3G femto 4G

RAN to Core lines of spec.

…the design is hard , but it is becoming more tractable


Buridan Universal Text and Telephony Company

awarded an operator’s

license, but couldn’t decide

whether to build a single

vendor RAN or multi-vendor

HetNet

?

The message?

Commitment Matters

Multi-vendor:

Multiple procurement, OAM

and training overheads

Take advantage of best-in-

industry roadmaps

Flexible to vendor corporate

strategy and pricing

Who’s the SI?

Optimal network

performance

Single vendor:

Simple procurement,

operations/maintenance and

training

Tied to single roadmap

High cost to change

Vulnerable to vendor

corporate strategy and pricing

Best effort network

performance


Schizophrenic vendors, they’re black and white

Vendors are ambivalent

towards interoperability

“If we’re trying to displacean incumbent,

we’re all for it.”

Vendors are ambivalent

towards interoperability

“ If we’re defending an

incumbency,

we move heaven and earth

to question the value of it.”


Operator Process, and who’s the SI?

Operator processes are still largely tuned to macro deployment:

• Operator A: “it takes us six weeks to deploy a cell”

• Operator B: “each cell we deploy touches 17 departments in my organisation”

• AT&T (SCA 2013): “we can’t order equipment to be installed at a location that

doesn’t have a street address – our tools won’t let us.”

Who fixes it when it’s broken

If it takes time to fix, then the customer will

lose patience and revert to the

tried-and-tested?


A message of hope…

Operator processes are still largely tuned to macro deployment, but are moving:

• Operator A: “it used to take us six weeks to deploy a cell. Now it takes us two

hours”

• Operator B: “each cell we deploy used to touch 17 departments in my

organisation. Now it’s two.”

• AT&T (SCA 2013): “we couldn’t order equipment to be installed at a location

that doesn’t have a street address – our tools wouldn’t let us. But now we

can.”

…the red tape was there, but with the right commitment, it’s now being cut



14

Small Cell Management

System

Small Cell

GatewayPublic/Private

Internet

EPC

(LTE)

BackhaulBasestations CoreGateway

Small Cell layer

MSC/GSN

(GSM+3G)

SecGW

Macro layer

Handset

RRC

X2,

Iu-r,

SON

IPSec

Iu-h, TR69/196v2

Iu, S1

The interoperable interfaces

are at least countable, and

based on standards


… but with a cloud-RAN on the horizon

15

Small Cell Management

System

Small Cell

GatewayPublic/Private

Internet

EPC

(LTE)

BackhaulRadio heads CoreGateway

MSC/GSN

(GSM+3G)

SecGW

Macro and small cell layer

handset

RRC

X2,

Iu-r,

SON

IPSec

Iu-h, TR69/196v2

Iu, S1

Fronthaul baseband

Security?

Transport , OAM incl.

SON?

Control and Data?

Cloud-RAN offers

another opportunity

to privatise the

interfaces, and force

operators towards a

single-vendor RAN



• Operators are vocally insistent on multi-vendor interoperability on key interfaces

• Incumbents will reluctantly agree to integrate in a multi-vendor context

• The “who’s the SI?” question remains an issue

• the answer is rarely “the incumbent”, though it’s expensive for the incomer

• Initiatives such as the SCF Interoperability Plugfests are removing the sting and the risk

from multi-vendor integration

• Technology such as Self-Organisation (centralised, distributed and hybrid) with

standardised interfaces and procedures will also reduce the SI burden.

• With these issues in place…

• Properly interoperable interfaces

• Technology to reduce the SI burden

• Exhaustive cross-industry laboratory pre-test

• Operator commitment, with business processes to match

…we can do it!

It can be done..


Nick Johnson

CTO, ip.access

Thanks for your attention…

[email protected]