RN2483 Range Test
3 likes808 views
The document summarizes an experiment testing the range and reliability of communication between two RN2483 LoRa modules placed at varying distances. The results show that communication was successful at closer distances (100m) with lower output powers (0dB) but required higher powers (14dB) over longer distances. The modules were more susceptible to failures at different heights. Recommendations include further testing the modules at elevated heights and varying frequency/bandwidth settings.
RN2483 Range Test
- 1. Page 1 of 6 RN2483 LoRa Module Report on Range Test carried out at @iLabAfrica on Friday 10th , June 2016. The tests were done by: 1.Reha Yurdakul 2.Kevin Mwega 3. Leonard Mabele Abbreviations: DFU: Device Firmware upgrade UART: Universal Asynchronous Receiver/Transmitter ADC: Analog to Digital Converter GPIO: General Purpose Input/Output FSK: Frequency Shift Keying SNR: Signal to Noise ratio ASCII: American Standard Code for Information Interchange dB: decibels rx: receive tx: transmitt
- 2. Page 2 of 6 Introduction The RN2483 is a low-power long range transceiver module based on wireless LoRa Technology. It utilizes unique spread spectrum modulation within the sub-GHz band to enable long range, low power and high network capacity. The low power performance capability of the RN2483 provides a longer battery life enhancing the ability of this small device to connect millions of wireless sensor nodes to Lora gateways and IoT-connected Cloud Servers. This module complies with the LoRaWAN Class A protocol specifications. It integrates RF, a baseband controller, command Application Programming Interface (API) processor that is easy to configure via simple ASCII commands through the UART, making it a complete long range Solution. LoRaWAN networks are laid out in a star topology in which gateways relay messages between end- devices and a central network server at the backend. Gateways are connected to the network server via standard IP connections while end-devices use single-hop LoRa communication to one or many gateways. All communication is generally bi-directional, although uplink communication from an end-device to the network server is expected to be the predominant traffic. All LoRaWAN devices implement at least the Class A functionality. Devices implementing more than Class A are described as “higher Class end-devices”. End-devices of Class A allow for bi-directional communications whereby each end-device’s uplink transmission is followed by two short downlink receive windows. Class A operation is the lowest power end-device system for applications that only require downlink communication from the server shortly after the end-device has sent an uplink transmission. RN248 handles this protocol between the configured end-devices where a host MCU reads a sensor and commands this module to transmit the sensor reading over the LoRa network. The RN2483 is described as having the following features: 1. Long range: greater than 15km 2. Low power consumption for 10+ year battery life 3. Operates in 433MHz and 868MHz bands 4. Embedded LoRaWAN Class A protocol 5. Easy to use ASCII command interface over UART 6. Supply voltage: 2.1-3.6V 7. Temperature range: -40°C to 85°C 8. Adjustable output power up to +14 dBm 9. High receiver sensitivity down to -148 dBm 10. Device Firmware Upgrade (DFU) over UART 11. 14 GPIO for control, status and ADC 12. Excellent interference immunity 13. Secure AES-128 encryption
- 3. Page 3 of 6 Experiment Description From the foregoing description of the LoRa RN2483 module features, the following team of three members carried out an experiment on the communication strength and reliability of two RN2483 modules positioned at varying distances: 1) Reha Yardakul – IBM 2) Kevin Mwega – IBM 3) Leonard Mabele – @iLabAfrica Two notebooks and two RN2483 modules were used in this experiment. One module was connected to one notebook and left stationary in the IoT Room on 5th Floor at @iBizAfrica while the other module was connected to the second notebook whose position was being shifted in three locations per floor from 5th Floor to the Ground floor. This experiment was being carried out to prove the reliability of the RN2483 in Long range communication (Feature 1 above) and the strength of communication between the two modules at the set output powers (Feature 8 above). The Arduino Serial command/response interface was used in this experiment. The commands used for the module were radio commands. The following radio commands were first used to determine the LoRa signal status of the two modules: radio get mod - reads if module is modulating in LoRa or FSK radio get freq - reads back the current frequency the transceiver communicates on radio get pwr - reads back the current transmit output power radio get sf - reads back the current spreading factor settings radio get afcbw - reads back the current automatic frequency correction bandwidth radio get rxbw - reads back the receive signal bandwidth radio get bitrate - reads back the current FSK bit rate setting radio get wdt -reads back the current time-out value applied to the watchdog Timer radio get bw -reads back the current operational bandwidth applied to transmissions radio get snr -reads back the measured SNR for the previous packet reception Most of the outputs of the following commands were similar for the two modules. The following two commands were used during testing of the communication capability of the two modules: radio rx - this command configures the radio to receive simple radio packets radio tx - this command configures a simple radio packet transmission The radio rx command is appended with a space and a zero (i.e. radio rx 0) to put the radio into continuous receive mode. The mac pause command was first used before radio rx and radio tx commands to initiate the module into transmission and reception mode.
- 4. Page 4 of 6 The following command was used to adjust the output power whenever communication failed or uncertainty of transmission-reception occurred to determine the best stable output power for successful transmission and reception of the send data. This was being done if the new shifted position by the second RN2483 module could not result to successful communication. radio set pwr <value> Experiment Results The following are the findings of this experiment. The results are tabulated using the following criteria: The Floor Number column indicates the floor on which the second RN2483 module was placed in a descending order i.e. starting from 5th floor. The position column indicates the points visited on each floor i.e. 1st , 2nd and 3rd position. The Output power column indicates the operating range of power from 0 to +14dB FloorNumber Position 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 5th 1 ✓ 2 ✓ 3 ✓ 4th 1 ✓ 2 ✓ 3 ✓ 3rd 1 X X X — — ✓ 2 X X X X X ✓ 3 X X X X X ✓ 2nd 1 X X X X X ✓ 2 X X X X X — — ✓ 3 X X X X X X — ✓ 1st 1 ✓ 2 ✓ 3 ✓ GF 1 X X X X X X X ✓ — — ✓ 2 X X X X X X X — ✓ ✓ 3 X X X X X X X X X X X X X X ✓ Output Power(In Decibels)
- 5. Page 5 of 6 From this table: A tick (✓) shows successful communication between the two modules at the given power output. A dash (—) shows an uncertainty in the communication between the two modules; a probability of successful communication exists in this case A cross (x) shows non-successful communication between the two modules Conclusions From the foregoing results of this experiment, the following are the conclusions made from my observation: 1. The RN2483 module performance depends largely on output power irrespective of the bandwidth at varied distances. 2. Communication between two modules of RN2483 at 0 dB is successful as long as the modules are closer to each other i.e.at a distance of approximately 100 meters and with few obstacles between them. Take the observation of the three points of 5th floor and 4th floor from the table above. 3. The longer the distance between the two modules, the larger the output power required for successful communication. 4. The RN2483 is susceptible to attenuation especially if the distance is at different heights 5. The fact that RN2483 implements class A of the LoRaWAN protocol, makes it a suitable low power communication device between two end-points. Hence, it is best used between two MCUs or a notebook and an MCU. For gateway construction, RN2483 is not the best device to be used due to class B and C feature deficiency. 6. To avoid distortion in performance for varied distances, a power output threshold of 14dB is best. 7. Antenna design is a key consideration when setting up two RN2483 modules for stable radio transmission and reception. The antenna should be made firm and facing up like in the stationary RN2483 module used in this experiment.
- 6. Page 6 of 6 Recommendations: The two modules should be tested with both of them at an elevated height we get to determine the distance they can successfully communicate at 0dB power and 14dB power. This is to enable us come up with the best position to place them for the best stable and reliable data transmission at a reduced distortion level in a production environment. Next time, we try to adjust the frequency and bandwidth levels to get different deductions on how the RN2483 gets to perform with these factors varied. References: RN2483 LoRa Technology Command Reference User’s Guide by Microchip Microchip documentation of RN2483 Low-power Long Range Technology Transceiver Module LoRaWAN Specification Document by N. Somin(Semtech), M. Luis(Semtech), T. Eirich(IBM), T. Kramp(IBM) and O. Hersent(Actility).