Communications
Panel discussion
ITE/IMSA 2016
Frank Neuperger
General Manger and CTO
SIMREX Corporation
SIMREX CORPORATION
Founded 1990
Located in Buffalo NY.
Systems integration and wireless technology development history.
Acquired assets and exclusive rights to Aria Wireless and GLB Electronics product lines 2001
Legacy Product was SCADA and high reliability telemetry for government/military/industrial applications.
Entered traffic market in 2004 with products based on proven core wireless technology.
SIMREX CORPORATION
•
Traffic/ITS – Card cage, wide band radios, GPS timing, sensors and other traffic/its related functions.
SCADA – Contact closure radio, VHF/UHF,
hazardous environments.
• Transportation -Aviation, Rail.
Military/Aerospace – Semi-custom variants of standard products.
VITAL SYSTEMS
NASA, Calibration of Shuttle Landing System.
FAA and International equivalents, Multiple
Applications including vital systems.
Aerospace Flight testing, range safety.
Chemical warfare detection.
Railway Control.
TRAFFIC APPLICATIONS
Interconnect controllers at street Intersections
Bridging Wire-line Interconnects
Coordination (GPS or radio)
Contact closures, pre-emption
Control of programmable signboards
Custom logic/algorithm capability (eg. Crosswalk)
Wireless ITS APPLICATIONS
Roadside Animal Detection and Warning (RADS)
Vehicle Safety Barrier runoff monitoring (I-75 SBCS)
Travel time by Bluetooth Monitoring
CCTV Cameras
Bridging isolated fiber runs
School zone flashers and crosswalk control
Firehall and truck based pre-emption.
DataMover
ODU (RS232)
WB (Ethernet)
DataMover™ Traffic Products
DataMover
DR(M)
DataMover
170 T(M)
DataMover
SS Traffic
DataMover
I/O
DataMover
ATC/2070
Firehouse Based Preempt
(DataMover Preempt)
New Remote Control
(DataMover IO Hand Held)
Ferry Boat Loading
Work Zone
Simsync (RMC)
Once per day GPS accurate time synchronization
Controller specific time/date message
Once per day contact closure
Vandal resistant
Quick installation
Electromechanical controller mode
Serial messages for Siemens (epac), Econolite and AB3418 compatible Controllers
RMC version is GPS antenna only (NMEA GPRMC message)
Ethernet/POE Extender
100 Mbit Ethernet up to 1800 feet Cat6 without mid-span devices.
Variants available that also provide 24V or 48V POE 12 - 25W.
Traffic Cabinet mounted base unit.
IP67 weather resistant termination unit
Termination unit provides 328 additional feet of cable drive.
Typical apps are to communicate with and power Cameras or Radios.
Turnkey Systems Solution
FDOT Roadside Animal Detection
Turnkey Systems Solution
FDOT I75 Beacon system
300 Nodes along ~50 miles of Highway, Solar powered IP solution
Wireless connection to all remote nodes.
Detect vehicles that hit the fence and land in swamp
Less than 15 second notification by SMS email, console.
SIMREX Proxy server Interface to FDOT Sunguide system.
Wireless Trends:
DEVICE COMMUNICATIONS
Less serial and more IP devices.
Wider digital bandwidth to support CCTV. Less analog.
Use of Bluetooth and Wifi MAC sniffing as travel time sensor.
More encrypted communication
FREQUENCY, MODULATION, Protocol
• Less use of 900MHz, more 5800, 4900 and 3600
• Some shift of 900 MHz to WB 900 MHz.
• Less hopping/GMSK/FSK and more OFDM.
• More Licensed frequencies available 4900, 3600, 1800 (Canada)
• 802.11 at many freq’s. TDMA at unlicensed freq’s.
TOPOLOGY
• Less use of central base and more corridors with backhaul
• Use tree/loop of fiber and last mile or 3 with radio.
Wireless Concepts
Radio Speed and Bandwidth
The Link Budget and Fade Margin
Fresnel zone clearance
Frequency, 900 MHz vs. 2400 or 5800 MHz
RF Interference
Antennas
Sharing unlicensed spectrum
Diagnostic tools
Radio Speed and Bandwidth
Higher data speed requires
Wider bandwidth (letting in more noise, thus less sensitivity)
and/or
Signal structure that requires higher SNR (signal to noise ratio) or lower noise floor.
For best range and interference rejection
Use the narrowest bandwidth possible
Use the lowest data speed possible.
Radio Network Topology
CENTRAL BASE, RADIAL REMOTES.
Single BASE and all remotes aim back at Base.
High central antenna susceptible to more noise/interference.
MESH
Grid of many peers that can find alternate paths between them.
Extensive use of omni antennas shortens range and requires ~4-5x as many radios to cover the same area.
Easy to deploy.
Bandwidth is non deterministic and affected by other users sharing the spectrum.
CORRIDOR
Engineered system of narrow beams that follow street corridors.
Excellent frequency reuse and bandwidth.
Low number of radios for given coverage.
Radios are individually configured for the topology.
The Link Budget and Fade Margin
• Link Budget
– Like a balance sheet with line items that add or detract from your
ability to have a viable link.
– The units of measure are dB, and dBm
– GOOD: RF power, antenna gain, more receiver sensitivity.
– BAD: cable losses, distance, higher frequency.
– A good sanity check and training tool to learn unmodeled losses.
The Link Budget and Fade Margin
• Fade Margin (a.k.a. System Operating Margin)
– The bottom line of the Link budget.
– The number of dB that the link exceeds or fall short of providing a
viable link. + is good - is bad.
• The MATHFree Space Loss = 20Log10(Frequency in MHz) + 20Log10 (Distance in Miles) + 36.6
RSL = Tx Power - Tx Cable Loss + Tx Antenna Gain - FSL + Rx Antenna Gain - Rx
Cable Loss
The Link Budget and Fade Margin
Unmodeled losses
What if measured RSSI (signal strength) is less than the predicted
received signal level with the fade margin calculator?
This difference is either a faulty component or antenna alignment or
unmodeled loss.
Common causes of unmodeled loss:
• Foliage
• Fresnel loss due to terrain or buildings
• Other more complex NLOS loss
• Desensitization due to strong signal nearby.
Catalog these unmodeled error types to build your RF path
engineering experience. Use a spreadsheet. In the future, you can
then more easily predict path viability without need of a link test.
Fresnel Zone Clearance
• Direct visual path (line of sight) is important but it is
not enough
• You need some need some extra clearance “r” in all
directions around the direct path line.
• r increases for lower frequencies or longer distance.
Fresnel Zone = 72.1 * Sqrt (d / (f * 4)) where d is in miles and f in GHz
Fresnel Zone Clearance
• Because of the wave nature of radio signals, grazing an edge can increase or decrease the strength of signals that are above or below the edge. The mechanism operates by constructive and destructive interference.
• The edge can be anything. Sideways: A building very close to the street. Above: A sign or bridge above the line of sight.
• If you can see from one antenna to the other, you have OPTICAL or VISUAL line of sight.
• If you have adequate Fresnel clearance, you have RF line of sight.
Fresnel Zone Clearance
Fresnel Loss Quantified
Fresnel Loss Quantified
Fresnel Loss Quantified
2 km (1.25 mi) RF path
Frequency = 900 MHz
Mid path obstruction cases at -25 m, 0m and +25m
Fresnel Losses:
-25 m = -1 dB (25% loss)
0 m = -6dB (75% loss), Just grazing.
+25 m = -24 dB (99.6% loss) ok with 30 dB fade margin!
From: http://people.ee.duke.edu/~gary/ECE486/ECE186lecture9.pdf
Line of Sight or Not
• Optical Line of Sight
• RF Line of Sight
• Non (RF) Line of Sight (NLOS)
• near Line Of Sight (nLOS)
Line of Sight or Not
• Optical Line of Sight
– Can see from one end to the other (possibly need telescope).
– Does not guarantee Received Signal Level (RSL) is acceptable.
– Even RSL is acceptable the signal can be distorted to the point of
very little throughput of force cyclic disconnect/reconnect attempts.
• RF Line of Sight
– Implies that the path has reasonable Fresnel path Clearance 0.6F1.
This mainly assures acceptable RSL.
– In a reflection free environment with full Fresnel clearance, this also
assures minimum distortion due to Multipath reflections.
Line of Sight or Not
• Non Line of Sight (NLOS)
– Can’t optically see from one end to the other.
– Can’t “RF see” from one end to the other without loss of signal due
to absorption (foliage) or scattering (foliage, wires, signs poles…).
– Multipath due to reflections is common.
– RF modulation called OFDM (Orthogonal Frequency Division
Multiplexing) can greatly diminish detrimental impact of Multipath as
long as RSL is above receiver threshold plus some fade margin.
Link Quality
• Is strong Received Signal Level (RSL) good enough?
a.k.a. RSSI
Link Quality
• With strong multipath (reflected signals) RSSI can
remain high but the signal is distorted and results in
poor throughput.
• Validate performance with bandwidth check.
• Investigate BW deficiencies with Interference check
and channel quality check.
Frequency, 900 vs. 2400 or 5800 MHz
• Higher frequencies
– Less Fresnel zone clearance required.
– More antenna gain with a specific physical size of antenna.
– Better antenna directivity with a specific size of antenna.
– Shadowed or blocked more easily in most cases.
– Better frequency reuse because of the ability to use narrow beam
width antennas.
• Lower frequencies
– For the same RF power EIRP and gain of antenna, allow a better
link budget.
– Have less allocated (unlicensed) spectrum
Frequency, 900 vs. 2400 or 5800 MHz
• PARAMETERS: ANTENNA GAIN, LOSSES, TX POWER,
RX SENSITIVITY
• With all parameters fixed, 915 MHz has ~8.5 dB
advantage over 2440 MHz.
• With all parameters fixed, 915 MHz has ~16 dB advantage
over 5800 MHz.
• BUT THE PARAMETERS ARE NOT REALLY FIXED!!
• 900 MHz penetrates foliage better but has less spectrum.
• 5800 provides excellent directivity (frequency reuse) and
wide bandwidth.
RF Interference
• Co-channel - same channel
• Desensitization – nearby band overpowers receiver front end
• Multipath – destructive cancelation of some part of your channel
• Intermodulation – mixing of 2 signals co-channel
• Harmonic – distortion component of another carrier -> co-channel
Interference Remedies (null steer)
• Antenna is aimed directly at the desired carrier but
also sees equal power interference at 30 degrees off of
the main beam.
C=carrier
I=interference
• C=0 dB I= -4 dB
• C/I is 4 dB in this case, marginal
Interference Remedies (null steer)
• Steer the null of antenna to suppress co-channel or
desensitization interference. Rotate by ~ 30 degrees
• Sacrifice 4 dB of carrier
C=carrier
I=interference
• C= -4 dB I= -17 dB
• C/I is 13 dB in this case, 9 dB (8x) improvement
Interference Remedies (null steer)
• Steer the null of antenna even more to suppress co-
channel or desensitization interference.
• Sacrifice 8 dB of carrier
C=carrier
I=interference
• C= -8 dB I= -30 dB
• C/I is 22 dB in this case, 18 dB (64x) improvement
Interference Remedies (polarization)
• Cross polarize antenna against the interference.
• Benefit can be 10 to 20 dB suppression with 15 dB as
typical.
• Vertical pol. is very common for SCADA systems.
• Test your environment with spectrum analyzer with
both vertical and horizontal polarization to validate the
amount of benefit.
• The benefit is realized as improved Carrier to
interference ratio (C/I or CIR) and possibly diminished
desensitization.
• Horizontal polarized omni available but premium price.
Interference Remedies (desensitization)
• Cross polarize antenna against the interference.
• Vertical separation WITH NO OVERLAP.
• Horizontal polarized omni available but premium price.
• Steep filters combined with the above can help
• Synchronization of radios (if supported).
Antennas
• Gain, dBi vs. dB vs. dBd
• Beamwidth vs. gain.
• Clearance to pole or nearby objects.
• Clamp to element clearance
• Use signals from rear of yagi antenna
• Splitters.
• Lightning Arrestors
Antennas
• Gain, dBi vs. dB vs. dBd
9 dBd = 11 dBi (2 dB difference)
• Beamwidth vs. gain.
Narrow beamwidth = higher gain
Antennas
• Lateral clearance to pole or nearby objects that are not in front of the antenna mast.
– 18 inches for 900 MHz yagi
– ½ panel dimension for panels.
– Increase distance for objects in front of antenna mast per Fresnel zone profile.
• Why? because these objects act as reflectors and distort the beam of the antenna. Further separation, means less distortion.
• Even non metallic objects can reflect. eg. concrete surface of pole.
• Mast clamp to Yagi element clearance
– As far back as mechanically possible without loss of grip on antenna boom in order to avoid interfering with rear reflector.
Antennas NOT
More Antennas NOT
Antennas
• Is it ok to use signals from rear of a yagi antenna
• Front = 9 dBd, rear = -15 dBd
Antennas on a Splitter
• Splitter 3.25 dB loss for each antenna
– 9 dB becomes ~5.6 dB antenna when including the cable/connector losses.
– 3 extra RF connections to seal.
– 2 extra vulnerable RF cables.
– Not aesthetically pleasing.
– Cost of spit antenna system is ~3.5x the cost of a single antenna.
• Use Back of Yagi?
– Using the rear of antenna yields 24 dB lower fade margin than the front.
– For nearby locals that would have 50+ dB of fade margin anyway, this still leaves 26 + dB fade margin.
– 2 way antennas available but high cost.
Lightning Arrestor
– Low cost = high feed through
• 300V to 600V typical
• Often advertised as “high power” good for “750W”
• Many high power arrestors don’t trigger until hundreds of volts have reached the radio.
• Gas tube is often single use and impairs communication after it has triggers.
– Higher cost = low feed through
• 3V to 10 v peak typical
• Optimized for lower power radios.
• Technically more difficult to make hence the premium price.
Radio Specmanship
Sensitivity
-108 dBm 1e-6 BER = -110 dBm 1e-4 BER for GMSK
FEC and retries improves the rating as well. Many manufacturers state sensitivity at high BER with retries and FEC turned on. It is impossible to know without asking.
Sensitivity and data rate.
You cant have the highest sensitivity and the highest data rate at the same time.
Unfortunately many bid specs don’t specify sensitivity at a specific data rate. Some seriously deficient radios capable of multiple data rates sometimes get selected by easily passing through this screening.
RF Power Control
1mW, 10 mW, 100 mW …. vs. 1 dB stepsBER –> Bit Error Rate
Sharing Unlicensed Spectrum
Spectrum issues
FHSS (frequency hopping) .
Separate channels (DSSS and DTS)
MAC sharing (802.11)
Radiation issues
Directional antennas to keep beamwidth narrow.
Polarization
Use minimal power. USE MINIMAL POWER.
BER –> Bit Error Rate
Path Planning Tips for ITS/Traffic:
• AP’s (Access points or Bases) for point to multi point corridor
systems should have the AP’s on elevated risers.
• Keep all antennas to the centroid of the corridor.
• Validate any exceptions with zoom photography.
• Ok to test worst case paths for each corridor.
Testing Results Spreadsheet should have:
• Speed of each RF link in each direction.
• Signal Quality of each link if available
• Measured RSL/RSSI of each RF link. Yellow flag if 20 db lower
than theory or stronger than -25 dBm.
• Theoretical free space RSl/RSSI of each RF link.
• TX/RX speed of ETH link to each radio (to validate new cable).
Path Planning and Testing Checklist:
• Spectrum Scan for each AP location. Record data for designer to do
frequency selection. If single polarity radio, test in both polarizations.
This can be a telescopic tripod test if budget is constrained.
Test Data spreadsheet:
• Speed of each RF link in each direction.
• Signal Quality of each link if available
• Measured RSL/RSSI of each RF link. Yellow flag if 20 db lower
than theory or stronger than -25 dBm.
• Theoretical free space RSl/RSSI of each RF link.
• TX/RX speed of ETH link to each radio (to validate new cable).
Comissioning/Benchmarking Checklist
• Visual sanity check on alignment of each antenna.
• Insist that installers use an optical sighting alignment tool on
narrow beamwidth panel antennas.
• Redo spectrum scan for each AP location if more than 90 days
since the RF path validation was done. Best frequency choice
may be different now.
Create Spreadsheet with:
• Speed of each RF link in each direction.
• Signal Quality of each link if available
• Measured RSL/RSSI of each RF link. Yellow flag if 20 db lower
than theory or stronger than -25 dBm.
• Theoretical free space RSl/RSSI of each RF link.
• TX/RX speed of ETH link to each radio (to validate new cable).
RF Path Validation in Traffic/ITS
– Actual test.
– Sanity check on Google maps .
– Photography.
Path Planning in Traffic/ITS
Path Planning in Traffic/ITS
Path Planning in Traffic/ITS
• Street level
Path Planning in Traffic/ITS
• Bucket truck at 35’
Path Planning in Traffic/ITS
– Use telephoto photography with high zoom 10 to 30x to
visualize/validate the clear centroid and any midpath obstructions.
– Locate the AP (master)antennas at each end so that the path is
centered in the tunnel. Locating on sidearms mid street or mid-lane
incase of median with corridors is best. Locate 8+ feet above the
sidearms to avoid shadowing of other sidearms midpath.
– Less desirable is diagonal shots from luminaires at side of stree
due to close range Fresnel obstructions such as lamp head of the
next luminaire. Locate well above luminaire if forced to do this.
Path Planning with Zoom Photography
Path Planning with Zoom Photography
Path Planning with Google Earth
Tools
Radio configuration software
Remote Diagnostics
WEB RF path analysis tools
Real time spectrum analyzer
Path Benchmarking Tool.
WEB tools at www.simrex.com “free tools”
Spectrum Analyzer
• Horizontal vs. vertical polarization noise floor
• Out of band vs. in band signals.
• Desensitization test.
• Recording all sweeps and results to file.
Standard
ITS/Traffic
Wireless Applications
System design and Commission
Wireless Network and PTZ Cameras
Simrex design/configuration. Customer installed.
100 IP Nodes and growing. 15 serial nodes.
Support controllers (serial or IP). Preemption (IP). PTZ cams (IP).
Some nodes solar powered.
Extension and bridging of fiber.
Fiber alternative was ~ 15x the cost.
Done in 1/4 of the time it would have taken to install fiber.
Simrex Datamover WB 5800 radios. 6-108Mbps & 6 –300 Mbps.
Simrex MS-5 managed switches.
Simrex pressurized PTZ IP Camera’s
Simrex CRMS network management software
Factory configured and staged for plug and play deployment.
System design and Commission
Wireless Network
Simrex design assistance and configuration. Customer installed.
~75 wireless IP Nodes and growing.
Support controllers (serial over IP or IP). PTZ cams (IP).
Extension of fiber.
Simrex Datamover WB 5800 radios. 6-108Mbps.
Simrex CRMS network management software
Factory configured and staged for plug and play deployment.
Unusual
ITS Wireless Applications
Turnkey Systems Solution
FDOT I75 Beacon system
300 Nodes along ~50 miles of Highway, Solar powered IP solution
Wireless connection to all remote nodes.
Detect vehicles that hit the fence and land in swamp
Less than 15 second notification by SMS email, console.
SIMREX Proxy server Interface to FDOT Sunguide system.
Turnkey Systems Solution
FDOT I75 Beacon system
300 Nodes along ~50 miles of Highway, Solar powered IP solution
Wireless connection to all remote nodes.
Detect vehicles that hit the fence and land in swamp
Less than 15 second notification by SMS email, console.
SIMREX Proxy server Interface to FDOT Sunguide system.
Turnkey Systems Solution
FDOT Roadside Animal Detection
26 beam traps along 1.4 miles of US41 in Everglades
Focused on protecting endangered Florida Panther
Developed long range low power IR beam trap.
Solar powered IP accessed solution (0.5W LINUX PC)
Logging of all events and battery voltage over time.
Wireless (DM-IO-900) connection to all remote nodes.
http://sim-rads2.eairlink.com/www/RADS/status.php
Turnkey Systems Solution
FDOT Roadside Animal Detection
TRAFFIC APPLICATIONS
Interconnect controllers at street Intersections
Bridging Wire-line Interconnects
Traffic light status, alarm status
Time synchronization (GPS or radio)
New schedule download.
Contact closures, pre-emption
Control of programmable signboards
Custom logic/algorithm capability (eg. Crosswalk)
Wireless ITS APPLICATIONS
Roadside Animal Detection and Warning (RADS)
Vehicle Safety Barrier runoff monitoring (I-75 SBCS)
Travel time by Bluetooth Monitoring
CCTV Cameras
Bridging isolated fiber runs
School zone flashers and crosswalk control
Firehall and truck based pre-emption.
SimSync and SimSync RMC.
Firehall Preempt.
Crosswalk controller.
DataMover DRM portshare.
Road-side Animal Detection System.
Fence line Breach Monitoring
Products developed at Dealer or end User
Request:
DataMover WB and options
Ethernet 1.5 - 300 Mbps
900 / 2400 /3600/ 4900 / 5800 MHz
12.5, 20 or 23 dBi integral antennas or dish/omni
Serial data option. Serial data + Ethernet
Mesh capability
DataMover WB and options
Ethernet 1.5 - 300 Mbps
900 / 2400 / 4900 / 5800 MHz
12.5, 20 or 23 dBi integral antennas
Selectable video optimized protocol standard.
Integral and External Antenna versions
Dual or quad radio capability
5, 10, 20 or 40 MHz Channels
Split antenna capability
POE , power supply and mast clamp included
Router or bridge capability.
Multiple video stream mode.
Serial data option. Serial data + Ethernet
Mesh capability
DataMover WB 2x2
Same as DM WD with the following exceptions
Ethernet 1.5 - 300 Mbps
2400 / 5800 MHz
Dual Gigabit ETH ports
19 or 23 dBi integral dual polarized antenna at 5800 MHz
30 or 34 dBi dish antenna.
SIMREX CRMS
(Central Radio Management System)
Radio network visualization and management
Map view as well as hierarchical view.
Monitor SIMREX radios and switches
Monitor availability of third party radios and devices
Email notification of alarms on all devices.
CONTACT :
Dlr_xxxx.com
SIMREX CORPORATION
www.simrex.com