7/27/2019 Cluster Intro

1/19

vMonitor Confidential

Cluster Design

What is Cluster?Cluster is group of networked devices

RTU are networked with Gateways

These networks are formed with the help ofSpread Spectrum radio system

7/27/2019 Cluster Intro

2/19

vMonitor Confidential

Spread Spectrum Radio

SPREAD

SPECTRUM RADIO

7/27/2019 Cluster Intro

3/19

vMonitor Confidential

Spread Spectrum Technology

Definition:Spread Spectrum technology is a type of RF

modulation that uses signals that are

intentionally made to be much wider band

than the information they are carrying in order

to make them more noise-like.

Principal features:

Hard to detect or demodulate

Can be distributed over a wide range offrequencies

Comes in two principal type of modulation:

Direct sequence and Frequency Hopping

Hard to exploit or spoof

Direct sequence SS Signal Photo

Frequency Hopping SS Signal Photo

7/27/2019 Cluster Intro

4/19

vMonitor Confidential

Frequency Hopping vs.Direct Sequence Spread

Spectrum - 2

Frequency Hopping (FHSS)

Breaks incoming data into smaller individual packets andtransmits them on separate frequencies

If a packet is not sent successfully on a given frequency, itis re-sent on a another frequency

By re-sending data that was corrupted, the methodbecomes inherently reliable

Receiver recompiles packets into original form

No matter how strong the interferer is the FHSS systemwill continue to communicate

7/27/2019 Cluster Intro

5/19

7/27/2019 Cluster Intro

6/19

vMonitor Confidential

Frequency Hopping vs. DirectSequence Spread Spectrum - 3

There are 79 frequency hops before any frequency is repeatedSpace between each frequency is 1 MHz covering a 79 MHZ band

7/27/2019 Cluster Intro

7/19vMonitor Confidential

SS VS NARROWBAND

7/27/2019 Cluster Intro

8/19

7/27/2019 Cluster Intro

9/19vMonitor Confidential

FREE SPACE LOSS

Free Space Loss:

-L = C + 20*log(D) + 20*log(F)

Where

L = Loss in free space

C = Calculation constant (36.6 if D is Miles or 32.5 if D is in Km)

D = Distance

F = Frequency in MHz.

7/27/2019 Cluster Intro

10/19vMonitor Confidential

Distance Loss at F=

in miles in km 900 MHz 2.4GHz 5.8GHz

1.6 mi 2.5 km 99 dB 108 dB 116 dB

3.1 mi 5 km 106 dB 114 dB 122 dB

5 mi 8 km 110 dB 118 dB 126 dB

6.2 mi 10 km 112 dB 120 dB 128 dB

10 mi 16 km 116 dB 124 dB 132 dB

Free Space Loss: -L = C + 20*log(D) + 20*log(F) Where L = Loss in free space C = Calculation constant (36.6 if D is Miles or 32.5 if D is in Km) D = Distance F = Frequency in MHz.

Typical Free Space Losses at

7/27/2019 Cluster Intro

11/19vMonitor Confidential

Cluster Design for vMonitor RTUs

Cluster design

7/27/2019 Cluster Intro

12/19vMonitor Confidential

Major Aspects of Clusterdesign

Number of wells in field

Geographic Spread of the field

Density of wells per sq. Km

Type of wells and data transfer requirements

Terrain and Locations

Telecom Infrastructure such as Height of tower, WILANBase station antennae. Etc.

Power Requirements

7/27/2019 Cluster Intro

13/19vMonitor Confidential

Design Consideration forCommunication Clusters

Short-hop radios EIRP < 100mW to make it licensed-free.Limit the cluster radius between 1 to 3 Kms.

Theoretically one Gateway can talk to 255 nodes. Ourpresent design is limited to only 50 nodes in a cluster. Allow10 more nodes for future additions.

This helps faster turn around time. Total round-tripresponse time of remote RTU to SCADA queries need to beless than 300 mS.

1 poll for MSV, 2 Polls for WIW/GLW wells, 5 to 6 polls for

ESP wellsIf all GLW/WIW/MSV wells in cluster, poll rate will be as lowas 1 RTU per min.

If all ESP wells in a cluster, poll rate will be 1 RTU per 2min.

7/27/2019 Cluster Intro

14/19vMonitor Confidential

Design Consideration forCommunication Clusters

Line of Sight is key issue in 2.4 GHz frequency band radios.Flat Areas will have better RF signal propogation. Uneventerrain makes RF propagation difficult.

Need higher length communication poles.

Gateway Site need to be higher location and higher pole.

Gateway locations away from any plants, pipe yards ormetal objects.

Line of sight to the nearest Telecoms Tower in the area

Type of Sector or Omnidirectional Antenne for WILAN radios

Path Loss Analysis from Wellhead to Gateway Site

Path Loss Analysis from Gateway Site to Telecoms Tower

7/27/2019 Cluster Intro

15/19

7/27/2019 Cluster Intro

16/19vMonitor Confidential

Cluster design for Fahud

Total 11 Communication ClustersEach cluster limited to 50-60 wellhead RTUs

2 adjacent communication clusters for Pilot Project

New RTU communication pole are 6 m in height

Gateway communication pole are 10 m in height

Small Yagi Antenna for Wellhead RTUs point to gateway site

At gateway we have 2 antennae, one Omni-directionalantenna to communicate with wellhead RTUs, another semi-

parabolic grid antenna for communication to Telecom Tower

7/27/2019 Cluster Intro

17/19vMonitor Confidential

Fahud Clusters & Gateways

7/27/2019 Cluster Intro

18/19

vMonitor Confidential

Fahud Cluster# 3

7/27/2019 Cluster Intro

19/19

vMonitor Confidential

Fahud Cluster# 5