# LoRa Communication Using TVWS Frequencies: Range and Data Rate
## 5 Discussions  
This work studies LoRa transmissions using the TVWS bands, and the maximum communication range with different bandwidth and spreading factor values is evaluated. The study covers three different scenarios: free space, outdoor: urban and rural, and indoor. Maximum range can be obtained by increasing the spreading factor and decreasing the bandwidth. As the data rate increases, the range reduces. The range of LoRa using TVWS bands is estimated based on the link budget calculations and the specifications mentioned in the datasheet for the LoRa hardware. The free space path-loss scenario gives a maximum theoretical range of 2137.9 km at the largest \(SF\) value and lowest bandwidth. However, it is not practically feasible due to the presence of obstacles and other interfering signals. These results can be useful for comparing the performance of LoRa at other frequencies. The maximum range with LoRa at TVWS frequencies using the free space path-loss model is 2137.9 km, more than double the range of 921 km at 868 MHz (ISM band) and almost 16 times that of 133 km at 2.4 GHz. The indoor range also varies from 32.35 to 117.8 m, much more than LoRa at 868 MHz bands or about 1.5 times that at 2.4 GHz band. These indoor calculations can vary with lower path-loss exponent values giving an even better range. For the outdoor scenario, the maximum communication range is about 7 km for urban and 32 km for rural settings with the Okumura-Hata model. In contrast, it is 4.6 km and 26 km, respectively, with the LoRaT-PLM model. This is better than 5 km for urban and 15 km for rural using 868 MHz and a maximum of 443 m for 2.4 GHz bands. The maximum data rate of 46.8 kbps for LoRa at TVWS frequencies is less than 250 kbps for LoRa at 2.4 GHz and almost similar to LoRa at 868 MHz with 40 kbps. Data-rate calculations also depend on the available bandwidth at different frequencies, the LoRa hardware used, and the distance between the transmitter and receiver [16; 28]. From these studies, it can be inferred that TVWS-based LoRa can be suitable for long-range applications in the outdoor scenario and for indoor applications with better coverage. Techniques for managing interference are also essential in such applications. Since it uses licensed bands, this approach can be useful to avoid the interference issues common in the ISM band. In addition, since the coverage is better, fewer gateways would be required reducing the hardware requirement. Technical challenges include the larger antenna size at the lower TVWS frequency bands, and much research is focused on reducing  
Figure 9: Comparison of the proposed LoRaT-PLM model with OH and model presented in [19] outdoor urban scenario—UDR as a function of distance. the antenna dimensions. A small printed inverted -F antenna (PIFA) embedded on the LoRa sensor node circuit board is designed for IoT applications and gives adequate gain over the 410-441 MHz LoRa frequency band [29]. A microstrip antenna, fabricated for being used with TVWS technology in the range of 477 to 1100 MHz, has also been designed that gives a sufficient gain in the desired band. This antenna is much smaller than a typical log periodic antenna and can provide moderate bandwidth [30]. LoRa operates in the unlicensed radio spectrum and the frequencies and number of channels allotted are often country-specific. This also poses challenges for the implementation of backend systems. The TVWS band presents a path-loss advantage over the unlicensed ISM bands (868 MHz and 2.4 GHz) due to the operating frequency. The recommended frequency ranges for TVWS regulations in different countries also vary, but the bandwidth and the number of channels available is greater. Various regions have the 433 MHz band, which is the ISM band designated for LoRa transmissions. Most of the allocations in this band support up to 125 MHz bandwidth [7]. As mentioned, TVWS bands are licensed and underutilized; the supported bandwidth can be extended to 250 KHz and 500 KHz, thus enhancing the data-rate capabilities.