Datasheet LoRaWAN prototype PCB v Table of Contents 1. Specifications Data rates... 3

Transcription

1 Datasheet LoRaWAN prototype PCB v1.0.1 Table of Contents 1. Specifications Data rates LoRaWAN TM... 3 Receive limitation... 3 Transmit limitation LoRa TM

2 1. Specifications Model name: Revision: Functionality: Dimensions (Length x Width): Location module type: Sensitivity: Max. update rate: Protocol: LoRaWAN prototype v1.0.1 Transmit location coordinates to user 45 x 25 mm GPS -165 dbm (High) 1 Hz (1 second) NMEA Transmit module type: LoRa TM Frequency: 868MHz (European allowed ISM band) Sensitivity: -148 dbm (High) Maximum Link Budget: 168 db Protocol: LoRa TM / LoRaWAN TM version 1.1 Cyber security: 3 layer AES-128 Key features: - Low power consumption; - Easy implementation with solar power module; - Small, can be fitted in tight places; - Low costs; - Open source network available (no telecom. subscription required); - Typical in cities more than 5 km connection range; - LoRa Tx/Rx inside building (excluded GPS); - Implemented Cyber Security IoT; - Low hardware maintenance; - Proven technology. Additional: LoRa TM & LoRaWAN TM functionalities will only increase in the future. For example, if the density of gateways in a country is high enough, it can replace the GPS functionality. Also the open source network is extending with the time. Since the gateway have several kilometres range, a country like the Netherlands is easily covered with low costs investment. 2

3 2. Data rates 2.1 LoRaWAN TM When wide area applications are required the existing LoRaWAN TM network can be used (when available in specific country). Receive limitation There are three data rate scenarios as per LoRaWAN TM 1.1 Specification released at October, Figure 1 Source: LoRaWAN TM 1.1 Specification, Copyright 2017 LoRa TM Alliance The class is programmable in the PCB. The required class is depending on the type of application. When the PCB should receive data/ commands instantly, Class C is required. When the PCB can receive data/ commands within a certain time limit, Class A or B will suffice. 3

4 Transmit limitation The transmission data rate is depending on multiple variables. First of all, the specific country regulations defines the limit of the maximum duty cycle. In Europe the ETSI EN states that the MHz band can have a maximum duty cycle of 1%. The formula for the availability of a node is: Ts = Ta ( 1 d 1) Ts = Time silenced (s) Ta = Time On Air (s) d = maximum duty-cycle in a sub-band In theory with the European rules this results in a maximum transmission time of 36 seconds/ hour in each sub-band for each end- device (extreme good conditions). Second limitation is the forwarding error correction (coding rate) required which is configurable in the gateway. Third limitation is the quality of the connection between the node and the gateway and the allowed bandwidth (125kHz in Europe). The formula for the data rate: DR = SF BW CR 2SF DR = Data Rate (bps) SF = Spreading Factor (7 12) BW = Bandwidth (Hz) CR = Coding Rate (4/5 to 4/8) Fourth limitation is the number of nodes per gateway. The limitation is cause by the amount of Tx/Rx collisions. The IEEE has released in January 2017 in the Communications Magazine an article with a test about the limitations of LoRaWAN. The article is called Understanding the Limits of LoRaWAN. Figure 2 - IEEE magazine January 2017 article shows the amount of applicable nodes per gateway 4

5 The same article shows a test which is applicable in the European LoRaWAN network. These figures can be used as a good indication about the maximum data rate a European LoRaWAN network can handle. Figure 3- IEEE magazine January 2017 article test results Note that LoRaWAN network providers use the own Access Policies that limits the uplink and downlink messages. Note that LoRaWAN standard limits the payload to 222 bytes for SF7 and 51 bytes for SF12 (LoRaWAN protocol adds 13 bytes to the payload). For example, the provider The Things Network has a Fair Access Policy of a maximum of 30 second per day per node uplink Time On Air and 10 downlink messages per day (24 hours) per node. On request Things Technology can design the required LoRaWAN network for your application. Please contact us at: info@thingstechnology.nl 2.2 LoRa TM For local application it s possible to design a LoRa only network. This network will not contribute to the LoRaWAN network which is being extended around the globe. Like the LoRaWAN network, the LoRa network is limited to the rules of the specific country and the collision by multiple nodes. In addition the receive windows are also assigned into three classes as described in the LoRaWAN paragraph. However, the benefit of a LoRa only network is that it s not limited by an Access Policy of a LoRaWAN network provider. Because of this it s possible to design the network to its described data limits by the law. When perfectly designed, this network could reach the following data rates (SF 7 condition): Payload (bytes) Availability (transmission per hour) Bitrate (bps) On request Things Technology can design the required LoRa network for your application. Please contact us at: info@thingstechnology.nl 5