Smart Metering: LoRaWAN vs. Sigfox vs. Weightless-P

Which LPWAN technology is most suitable for Smart Metering?

This article compares the leading LPWA (low power wide area) technologies and their ability to meet the requirements of a smart metering deployment in a dense region in Europe and the United States.

For a conservative comparison, let’s use half hourly readings as our baseline. Which means…

Each Smart Meter will be only be sending…

1)  48 messages sent per day

2) 12 byte per message

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Number of Base Station(s) required to support a full Smart Meter deployment in Levallois-Perretis, France. 

Region (Europe): Levallois-Perretis

Levallois-Perretis a commune in the northwestern suburbs of Paris, France.

Number of households / Smart Meters: 34,180

Area: 2.41 km2 (0.93 sq mi)

LORA:                 4

Sigfox:                2

Weightless-P:  1

 *detailed calculations below


Number of Base Station(s) required to support a full Smart Meter deployment in San Francisco, California. 

City (United States): San Francisco 

Number of households / Smart Meters: 376,942

Area: 121.4 km² (46.9 square miles)

LORA:                 8

Sigfox:                15

Weightless-P:  5

 *detailed calculations below


 

Why the criteria of 48 messages / day ; 12 byte messages was chosen..

The Smart Metering data is used differently by different levels of the service chain.

Suppliers

  • Meter readings – for billing purposes
  • Half Hourly readings – for additional services or sophisticated products
  • Maintenance messages about the health of the meter – such as memory problems
  • Firmware messages – to update the software in the meter
  • Configuration messages – to set up new products
  • Pay As You Go messages – to top up PAYG credit
  • Tamper messages – to detect theft and security attacks
  • Export meter readings – to measure how much electricity your solar cells or wind turbine is passing back to the network for load management and to credit the customer depending on the commercial arrangement.

Distribution Network Operators

  • Power outage messages – to know when and where outages occur
  • Meter readings – for network billing to suppliers
  • Half Hourly readings – for network load planning
  • Voltage and Power Factor readings – for network operation and planning.
  • Export meter readings – for network operation and planning.

Other Authorised Parties

  • Meters readings – to analyse and show you your energy usage
  • Half Hourly readings – to analyse and show you your particular energy profile shape.

 

Smart Meter Capacity Calculations

Figure 1: Mac Throughput (Europe)

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Figure 2: Number of Smart Meters supported per Base Station (Europe)

(based on criteria: 48 messages per day ; 12 byte messages )

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Figure 3: Mac Throughput (United States)

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Figure 4: Number of Smart Meters supported per Base Station (USA)

(based on criteria: 48 messages per day ; 12 byte messages )

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Sources:

  1. http://www.smartme.co.uk/how-they-work.html
  2. http://statisticalatlas.com/place/California/San-Francisco/Overview
  3. http://www.map-france.com/Levallois-Perret-92300/housing-Levallois-Perret.html
  4. http://www.ubiik.com/lpwan-comparisons

The 3 Major Flaws of LoRaWAN

LoRaWAN has three undeniable flaws

  1. Nearly all uplink messages are unacknowledged (you won’t know if the message was ever successfully delivered)
  2. All gateways in range see all uplink traffic (not safe)
  3. LoRaWAN requires an enormous amount of bandwidth (tough to scale, culprit for ISM band traffic, subject to interference from other LoRaWAN gateways)

 

1. Nearly all uplink messages are unacknowledged

LoRaWAN has 1% Duty Cycle Limit for both end devices and the gateway (A duty cycle is the fraction of one period in which a signal or system is active. A period is the time it takes for a signal to complete an on-and-off cycle) In order to support the 1% duty cycle limitation for the gateway, all uplink messages are unacknowledged and uncoordinated, LoRaWAN is considered a “pure-aloha” scheme.

What is pure-aloha: “The idea is applicable to systems in which uncoordinated users are competing for a single channel (shared resource). ALOHA permits users to transmit any time they feel like. Collisions will occur and therefore colliding frames will be destroyed. However, if feedback is available on the destruction, then users will be made aware of their frames have not been transmitted (received) successfully  (1)

“Such a network has about 18% efficiency. This means that 82% of packets are lost when a LoRaWAN network is fully utilized. Since most messages are unacknowledged, the end node does not know its message was missed”(2). The Things Network also confirms this statement by stating “the capacity for downlink messages is even lower than for uplink messages, so don’t waste it.”

2. All gateways in range see all uplink traffic (not safe)

No explanation required.

3. LoRaWAN requires an enormous amount of bandwidth

see my previous post: LORA vs. Sigfox vs. Weightless-P

Sources:

1: Notes on the efficiency of ALOHA: http://www.csee.umbc.edu/~chettri/cs481/notes/NotesOnTheEfficiencyOfALOHA.pdf

2.Link Labs Blog: https://www.link-labs.com/use-cases-and-considerations-for-lorawan/

3. https://iotee.wordpress.com/2015/12/08/lpwan-technology-comparison/