LORA Module in SignalPro

What is LORA? 

LoRaWAN is a high capacity, Long Range, open, Low Power Wide Area Network (LPWAN) standard designed for LoRa Powered IoT Solutions by the LoRa Alliance. Where LoRa is an RF modulation technology for LPWANs. The name, LoRa, is a reference to the extremely long-range data links that this technology enables. LoRa was created by Semtech (https://www.semtech.com/lora ) to standardize LPWANs. https://lora-developers.semtech.com/library/tech-papers-and-guides/lora-and-lorawan/#:~:text=What%20are%20LoRa%C2%AE%20and,links%20that%20this%20technology%20enables.&text=They%20often%20offer%20both%20LoRaWAN,M1%2C%20which%20are%20complementary%20technologies.

Designed to wirelessly connect battery operated things to the Internet in regional, national or global networks, the LoRaWAN protocol leverages the unlicensed radio spectrum in the Industrial, Scientific and Medical (ISM) band.

Characteristics of LoRa

Open

The technology stack below shows how LoRaWAN operates. LoRa is the physical (PHY) layer, which means it is the wireless modulation used to create the long-range communication link. LoRaWAN is an open networking protocol that delivers secure bi-directional communication, mobility, and localization services standardized and maintained by the LoRa Alliance.

Open

Picture from Semtech*

LORAWAN uses the star network as opposed to MESH, the typical network architecture below

LORA Module Feature Sets

The LoRa Module is designed to ensure the user is able to plan, optimize and simulate the real-deployment scenarios, resulting in accurate plans.

The LORA Module supports EU 868 and US 915 frequencies. Between these frequencies majority of the globe is covered. Channel plans in table below

The frequency range designated to LoRa Technology in the United States, Canada and South America is 902 to 928 MHz. This frequency range is known as the 915 MHz frequency band.

The LoRa Frequency band is divided in to the following channels for US (Based on the FCC part 15 Document):

In SignalPro you can set the frequency in the system details, as below by navigating to Network Design/ Analysis > LoRa/ IoT Networks > System details/ Service area in the menu bar.

Selecting edit in this GUI, will open the Adaptive Modulation Editior, where you are able to define the Spreading Factor, bandwidth, data rate, power offset, C/I+N), noise and thresholds.

• For a fixed channel bandwidth, the higher the spreading factor, the higher the processing gain, resulting in an increase in sensitivity and, therefore, an increase in link budget. Subsequently, however, the time on air will also increase.

• Orthogonality between spreading factors allows for the transmission of multiple LoRa signals that are both on the same channel frequency and in the same time-slot.

• For a fixed SF, a narrower bandwidth will increase sensitivity as the bit rate is reduced.

• The Code Rate is the degree of redundancy implemented by the forward error correction (FEC) used to detect errors and correct them. This rate is fixed at 4/5 for the LoRaWAN protocol

What is Spreading Factor?

Spreading factor is what determines the speed of a chirp. For reference “chirps” is a signal with frequency moving up or down (up-chirp or down-chirp respectively) with a different speed.

LoRa is a spread spectrum based modulation meaning that the signals are essentially orthogonal to each other, when different spreading factors are transmitted on the same frequency channel they do not interfere with each other. Rather the signal with different spreading’s factors are seen as noise to each other.

Most importantly as the spreading factor changes, the effective data rate also changes. Allowing the preservation of battery life of connected end nodes by making adaptive optimizations of an individual end node’s power levels and data rates.

The amount of spreading code applied to the original data signal is called the spreading factor (SF). There are a total of six spreading factors (SF7 to SF12). The larger the spreading factor used, the farther the signal will be able to travel and still be received without errors by the RF receiver.

SignalPro supports the various topologies for LORA deployments such as star topology with point to multipoint or point to point. The studies included are:

• Best Available LoRa downlink data rate

• Best Available LoRa uplink data rate  

• Number of LoRa servers above the uplink threshold

• LoRa optimized uplink transmit power

• Lora bidirectional margin

• Best available LoRa downlink spreading factor

• Best available LoRa uplink spreading factor

This Coverage Map is of the Spreading Factor 12 and Data Rate of 0.25

This Coverage Map is of the all 12 Spreading Factors and associated Data Rates

 Automatic Router Placement Features

The purpose of automated router planning for the LoRa Module is to automate candidate planning using sophisticated algorithms based on inputs. Once you have defined your LoRa sites you may go into the automated router planning.

• You may browse and test a previously existing sample file.

• Set up the propagation model for which is to be used for the analysis.

Automatically Calculate Router Locations:

1. From the CPE group selection for hub creation drop-down list

2. Choose the CPE group you want to use for the automated process.

3. Click the Automated Router Selection button, this will bring up the following dialog box

• The “Use installed Routers in selection process” will take previously created sites and assume that they are already active. This option will look to improve coverage by adding addition sites to the existing active sites.

• You must give a new group name and choose the template you wish to use for the routers.

• The options within the middle allow you to set your router range and signal level target. The options you select will be used in whichever method you choose.

• Method 3 is recommended because it calculates the IOT systems, which pertain to the LoRa system.

When selecting method 3 you are presented with the following dialogue:

• If a .bna file with multiple polygon regions is selected here the algorithm will find a router solution for each area independently. This can allow large projects with distinctly-separate geographic areas to run more quickly.

• The router range and signal level threshold are carried over from the previous menu.

• Set the coverage limits . Max or min coverage limits for candidate selection

• The “Use costs for planning” checkbox allows the algorithm to consider relative costs of site locations in the solution. This feature will be covered in more detail in a separate article.

• The Run Optimization values configure how the algorithm chooses initial solutions to consider and how many iterations it runs to look for better solutions. Click the “setup best grid and tx separation” to have it automatically set the Tx separation and Grid distance values. The Number of trials and cooling steps can be increased to allow it to continue seeking better solutions, but the default values are often sufficient.

Selecting “Setup Modulation Scheme” the following GUI will appear

The modulation to be used on the uplink and downlink should be defined here, either from file, defaults or create a new table. This will be used for the capacity plan.

Once you click the Run Optimized Capacity Planning button you are presented with a new window that will display the useful sites found and the subscribers they serve. It will display how many sites were found and what percent coverage they provide.

• You can also choose to add in additional sites with the “+add” button. When the “+add” button is turned on, you can simply click on the candidate locations to add new sites and see the subscriber units they serve.

• You can toggle routers active and inactive with the “X toggle” button. With the “X toggle” button turned on, you can click on a router turn it inactive and adjust the design. Click back on the router to turn it back to active.

When the router locations are acceptable, click “Yes” at the bottom of the window to accept the new routers and the created transmitter group. You may also click “No” to reject the candidate routers and go back to the Optimized Capacity Planner and make adjustments.

When the router locations are acceptable, click “Yes” at the bottom of the window to accept the new routers and the created transmitter group. You may also click “No” to reject the candidate routers and go back to the Optimized Capacity Planner and make adjustments.

In the capacity planner the report can be assessed and saved.

1. Chose to accept the plan and candidate sites from auto placement

2. Select ok

Below is the auto placement selections with the towers (blue dots)

When you open the TX database you will find the new selections