Whether private or public, overlapping networks in a specific geographical area will share the medium, and therefore the collision rate will increase.

The common techniques which can be used to alleviate this situation is the use of Clear Channel Assessment, which evaluates the "cleanness" of a channel by using spectral scanning techniques (and therefore adapt the channel plan), and implements retries in packet transmission to maximize success rate.

When it comes to the access point side (gateways), the use of the"private" sync word versus "public" sync word is useful to ensure that the gateways don't report a vast majority of the incoming traffic using a different setting.

Each SX1257/50/55 chip can digitize almost 1 MHz of spectrum, therefore two are required typically to achieve 8 channels with a channel separation of 200 kHz or so.

The limitation of using a single SX1257/50/55 chip and one SX1301/08/02 chip is that you can only digitize 1 MHz of spectrum (and not 2 MHz) and can only build a 4 channel modem since the channels are spaced 200 kHz apart.

For noise immunity (digital to RF), it is safer to use a separate 3.3 V power rail between SX1308 baseband chip and SX1257 RF transceivers.

SE2435L RF front-end uses two power rails: 3.3 V (VCC0) and 2.0 V (VCC1 and VCC2). Concerning the 3.3 V (VCC0), it is already shared with the 3.3 V LDO SX1257 radio_A on the reference block diagram and schematic of Picocell Gateway. You can keep it this way.

You can share the same 3.3 V power rail between the two SX1257 radio_A and radio_B RF transceivers.

This 3.3 V power rail can also be used to supply the 32MHz TCXO.

In summary, two separate 3.3V power rails are recommended:

  • the first one to supply SX1308 baseband chip
  • the second one to supply the two SX1257 radio_A and radio_B RF transceivers, VCC0 of SE2435L RF front-end and 32 MHz TCXO.

For more details, see the Picocell Gateway reference design.

The gateway power consumption is mostly independent of incoming traffic.

We're speaking about a couple of watts (below 10 watts), but for a precise answer please get in touch with your gateway maker. The overall consumption depends on the supply strategy, peripherals, CPU used, and backhaul among others.

There is no definite answer to this question as it depends on four dimensions:

  • RSSI/SNR of the received packets (simultaneous reception on the same channel)
  • Time-on-Air of the packets (equivalent to data rate, the longer the packet, the longer one demodulator of the gateway is used)
  • Frequency of the packets (two packets with the same data rate and the same RSSI/SNR will collide unless they are on two different frequencies).
  • Number of times per day an end device will send a packet (taking resources another node could use)

In Europe LBT+AFA ( Listen-Before-Talk + Adaptive-Frequency-Agility ) is not desired or implemented, however in certain regions LBT is mandated.

The Corecell reference design now implements LBT, specifically to be in compliance with regulations in Korea and Japan.

No, you do not need a gateway. You can easily implement simple protocols using LoRa, either with modules or with the chips themselves.

Note that LORaWAN layer 2 protocol requires the use of a gateway, or alternately a Relay with gateway

The SX1301 device is the baseband signal processor for LoRa gateways. It takes 32 MHz, 1-bit I/Q digital baseband samples as an input. It is generally paired with two SX1257 front end digitizers, though it can be used with other forms of digital RF. This is often done with the 8 x SX1301 gateway architecture Senet uses in its network deployment.

Lora gateways or concentrators are designed to be used in long range star network architectures and are utilized in a LoRaWAN system. They are multi-channel, multi-modem transceivers and can demodulate on multiple channels simultaneously and even demodulate multiple signals on the same channel simultaneously due to the properties of LoRa.

The gateways use different RF components than the end-point to enable high capacity and serve as a transparent bridge relaying messages between end-devices and a central network server via standard IP connections while end-devices use single-hop wireless communication to one or many gateways.

All end-point communication is generally bi-directional, but also supports operations such as multicast enabling, software upgrade, over the air or other mass distribution messages to reduce the on air communication time.

There are different gateway versions depending the desired capacity and installation location (home vs. tower).

The term gateway and concentrator are both used, but they are equivalent components in a LoRa system. In other industries the definition of gateway and concentrator may imply different components.

Gateway reference designs exposed and made available in www.semtech.com have no license fees. For any other reference design please reach out semtech sales team.

The gateway reference designs are specified to coexist with 3G, and more importantly with 4G base stations, when co-located with a 4G base station with 50 dB of antenna isolation. The main risk is the injection  by the LoRa® GW of noise into the LTE uplink band 20, but this is taken care of  by the Semtech  reference designs.

Capacity is, first and foremost, a consequence of the number of packets that can be received in a given time. A corecell SX1302 based design with 8 channels can receive approximately 1.5 million packets (50Byte) per day using LoRaWAN protocol.

So, if your application sends one packet per hour, then a single SX1302 gateway can handle about 62,500 end devices.