LoRa and LoRaWAN – Part 6: Introduction and Comparison of LoRaWAN Concentrators and Transceivers Across Generations Leave a comment
Introduction and Comparison of LoRaWAN Concentrators and Transceivers Across Generations
In the previous section, we examined Duty Cycle, coding rate, and packet structure in the LoRa protocol. Now that we are familiar with the nature and overall operation of the software, it is time to turn to the hardware aspect. All LoRa communications are ultimately handled by something called a LoRa Concentrator. These chips are produced by Semtech and are essentially the heart of all LoRaWAN gateways.
To date, Semtech has introduced four different generations of LoRa concentrators, and all gateways available on the market use one of these as the main component for receiving and transmitting LoRa messages.
For a more complete introduction to LoRa products, you can visit Semtech’s official products page. In addition, RAK Wireless has provided a very good introduction and analysis of existing LoRa hardware, which helps make selection easier.
LoRaWAN® Concentrators
In this section, we provide a quick overview of each LoRa concentrator so you know what their differences are and which one is more suitable for what application.
The SX1301 is the first LoRaWAN concentrator produced by Semtech, designed for use in outdoor gateways. This chip operates in global ISM bands and was the first digital baseband chip to integrate Semtech’s LoRa Concentrator IP.
Some key specifications of the SX1301:
- High sensitivity up to -142.5 dBm (using the SX1257 Tx/Rx front-end model)
- Ability to reject strong interference (CW interferer rejection) up to 70 dB at 1 MHz offset
- Capability to operate in negative SNR conditions with CCR up to 9 dB
- Simultaneous simulation of 49 LoRa demodulators and one (G)FSK demodulator
- Dual digital interface for transmitter and receiver (TX & RX)
- 10 parallel programmable demodulation paths
- Support for Dynamic Data-Rate (DDR) for data rate adaptation
- Support for true antenna diversity or simultaneous operation in two frequency bands
The SX1301 laid the foundation for the first generation of LoRaWAN gateways, but it was later replaced by the SX1302, which offers lower power consumption and better processing power.
The SX1302 is the successor to the SX1301 and represents a significant upgrade in nearly every aspect. This chip reduces power consumption, offers better thermal performance, comes at a lower cost, and can handle more traffic compared to the previous generation.
Key features of the SX1302:
- High sensitivity up to -141 dBm (using the SX1250 Tx/Rx front-end model)
- Support for LoRa reception on 125 kHz channels with the following capabilities:
- 8×8 LoRa Packet Detectors
- 8 LoRa demodulators for SF5 to SF12
- 8 LoRa demodulators for SF5 to SF10
- LoRa demodulator for 125 / 250 / 500 kHz bandwidths
- One (G)FSK demodulator
- Direct connectivity to Semtech transceivers (SX1255, SX1257, and SX1250)
- Operation with a single 32 MHz clock
Overall, the SX1302 is more power-efficient, more cost-effective, and has greater capacity for message management. Following this generation, the SX1303 chip was introduced, which further evolved the path of the SX1302 with additional features.
The SX1303 is the generation following the SX1302 and is currently the most modern LoRa concentrator. This chip is fully pin- and size-compatible with the SX1302, but it further reduces current consumption, provides better thermal performance, and has a lower production cost.
One of the key features added to the SX1303 is support for geolocation using the Time Difference of Arrival (TDOA) method. This capability is enabled through a new feature called Fine Timestamp.
Key features of the SX1303:
- Fine Timestamp for precise geolocation (TDOA Geolocation)
- High sensitivity up to -141 dBm (with the SX1250 front-end)
- LoRa reception on 125 kHz with:
- 8×8 LoRa Packet Detectors
- 8 LoRa demodulators for SF5 to SF12
- 8 LoRa demodulators for SF5 to SF10
- Ability to receive up to 8 packets simultaneously when Fine Timestamp is enabled
- LoRa demodulator for 125 / 250 / 500 kHz bandwidths
- (G)FSK demodulator
- Direct support for Semtech transceivers (SX1255, SX1257, and SX1250)
- Single 32 MHz clock unit
In summary, the SX1303 is the continued evolution of the SX1302 with lower power consumption, reduced cost, and precise geolocation capability, making it an excellent choice for the new generation of LoRaWAN gateways.
The SX1308 is another LoRa concentrator from Semtech, but it has lower sensitivity compared to the SX1301/1302/1303 models. This chip is primarily designed for indoor gateways, where long-range or very high sensitivity is not required.
Key features of the SX1308:
- Sensitivity up to -139 dBm (with the SX1257 or SX1255 front-end)
- Ability to reject strong interference up to 70 dB at 1 MHz offset
- Capability to operate in negative SNR conditions (CCR up to 9 dB)
- Simultaneous simulation of 49 LoRa demodulators and one (G)FSK demodulator
- Dual digital interface for Tx and Rx front-ends
- 10 parallel programmable demodulation paths
- Support for Dynamic Data Rate (ADR) to optimize data rate
- Support for true antenna diversity or simultaneous operation on two bands
In summary, the SX1308 is a simpler and more cost-effective version chosen for indoor scenarios; whereas the SX1301/1302/1303 are primarily used for professional and outdoor gateways.
LoRaWAN® Transceivers
In addition to the gateway chips introduced in the concentrators section, another important part of the LoRa ecosystem is the transceiver chips. These chips are essentially the heart of end devices and sensors, as they handle both data transmission and reception.
Semtech has produced several well-known families of sub-GHz LoRa Core™ transceivers, the most widely used of which are:
- SX127x series
- SX126x series
- LLCC68 chip
Recently, Semtech has also introduced the LR1110 solution as part of the LoRa Edge™ platform, which, in addition to LoRa transceiver functionality, includes additional capabilities such as geolocation.
In this section, we will provide a quick overview of the most commonly used LoRa transceivers to understand their features and where they are primarily applied.
SX127x
The SX127x series was one of the first LoRa transceivers to hit the market, paving the way for LoRaWAN network development through its combination of long-range communication and high interference resistance. All chips in this family share similar specifications, with the primary difference being their operating frequency ranges:
- SX1272/73: Operate in the 860 to 1000 MHz band.
- SX1276/77/78/79: Cover a wider range from 137 to 1020 MHz.
Key features of the SX127x series:
- Built-in LoRa modem
- Maximum Link Budget of 157 dB for SX1272/73 and 168 dB for SX1276/77/78/79
- RF output up to +20 dBm at constant 100 mW power
- High-power amplifier for TX up to +14 dBm
- Programmable data rate for FSK modulation up to 300 kbps
- High sensitivity: up to -137 dBm for SX1272/73 and -148 dBm for SX1276/77/78/79
- Noise-resistant front-end: IIP3 = -12.5 dBm for SX1272/73 and -11 dBm for SX1276/77/78/79
- Excellent blocking immunity
- Low receive-mode current: only 10 mA for SX1272/73 and 9 mA for SX1276/77/78/79, with register retention in the nanoamp range
- Integrated synthesizer with 61 Hz frequency resolution
- Support for multiple modulations: FSK, GFSK, MSK, GMSK, LoRa, OOK
- Built-in bit synchronizer for clock recovery
- Preamble detection
- RSSI dynamic range up to 127 dB
- RF Sense and Channel Activity Detection (CAD) with ultra-fast automatic frequency control (AFC)
- Packet engine up to 256 bytes with built-in CRC
- Built-in temperature sensor and battery voltage indicator
In summary, the SX127x series is the classic and widely used LoRa transceiver family, still found in many common modules (such as Ra-02 or RFM95).
SX126x Series
The SX126x series is the next generation of LoRa transceivers after the SX127x, specifically designed for long-range applications with very low power consumption. All chips in this family are half-duplex, meaning they cannot transmit and receive simultaneously, but they are optimized for extended battery life and high output power. Another key feature of this series is the use of highly efficient internal PAs, which enable higher output power levels. In addition to LoRa, these chips also support (G)FSK modulation, allowing them to be used in legacy scenarios. The main difference between members of this family lies in the final stage of the transmit chain (TX Chain), which affects the maximum output power:
- SX1261 and SX1262: Provide global frequency coverage.
- SX1268: Specifically designed for Chinese frequency bands.
Key features of the SX126x:
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LoRa and FSK modem
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Maximum Link Budget = 170 dB (for SX1262 and SX1268)
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Output power:
- +15 dBm for SX1261 (with DC-DC or LDO)
- Up to +22 dBm for SX1262 and SX1268 (direct battery supply)
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Low receive-mode current: only 2 mA
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Integrated internal DC-DC converter and LDO
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Programmable data rate:
- Up to 5 kbps for LoRa
- Up to 300 kbps for FSK
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High sensitivity up to -148 dBm in LoRa mode
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High blocking immunity up to 88 dB at 1 MHz offset
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Co-channel rejection up to 19 dB for LoRa
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Support for multiple modulations: FSK, GFSK, MSK, GMSK, LoRa, and even Long Range FHSS (SX1262 only)
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Automatic CAD (Channel Activity Detection) with ultra-fast frequency control (AFC)
In summary, the SX126x offers lower power consumption, higher sensitivity, and greater output power compared to the SX127x. This makes it a more popular choice for modern IoT devices and sensors that require long battery life.
LLCC68
The LLCC68 is a sub-GHz LoRa transceiver from Semtech, primarily designed for indoor applications or short-to-medium-range indoor-to-outdoor communications (such as smart home scenarios). This chip is fully pin-to-pin compatible with the SX1262 and shares very similar features. In simple terms, the LLCC68 is a lighter and more cost-effective version of the SX1262, tailored for moderate and residential applications. It offers good power consumption and output power, but since it does not support all LoRaWAN spreading factors, it is less flexible than the SX1262 for large-scale networks and industrial scenarios.
LR1110 The LR1110 is not just a simple LoRa transceiver; it is a complete, multi-purpose solution that includes geolocation and environmental scanning capabilities in addition to the transceiver. For this reason, it is part of the LoRa Edge™ platform and is designed for smart applications such as asset tracking, logistics, and industrial IoT. This chip consists of several key sections:
Transceiver Features
- Support for LoRa and (G)FSK modulation
- Support for global ISM bands in the 150 to 960 MHz range
- Low-noise RX front-end for higher sensitivity in LoRa and (G)FSK
- High-power PA path up to +22 dBm
- Optimized PA path up to +15 dBm
- Long Range FHSS modulator for more robust communications
- Integrated PA regulator to simplify +15 / +22 dBm power selection on a single board
- Support for multi-region BOM design; compliance with local regulations is achieved simply by adjusting the matching network
- Full compatibility with SX126x chips and the LoRaWAN® standard
Geolocation Features
- GNSS positioning (support for GPS, BeiDou, and geostationary satellites)
- Ultra-low-power passive Wi-Fi scanner (802.11 b/g/n)
- Frequency synthesizer covering 150 to 2700 MHz
- High-bandwidth receiver ADC (up to 24 MHz Double Side Band)
- Internal digital baseband processing
The LR1110 is an all-in-one chip: a high-power, high-sensitivity LoRa transceiver combined with a versatile multi-mode geolocation tool using GNSS and Wi-Fi. This makes it an outstanding choice for smart tracking devices, logistics management, and industrial IoT.
In summery, introduction and Comparison of LoRaWAN Concentrators – Semtech’s SX1301 (first-gen, -142.5 dBm) evolved into SX1302 (lower power/cost) and SX1303 (adds TDOA geolocation via Fine Timestamp); SX1308 suits indoor use (-139 dBm). Transceivers: SX127x (legacy, up to +20 dBm), SX126x (ultra-low power, +22 dBm), LLCC68 (cost-effective indoor), and LR1110 (LoRa Edge with GNSS/Wi-Fi scanning). Essential hardware for gateways and end devices.
