Difference between LoRa and NB-IoT
LoRa and NB-IoT are the two most promising low-power WAN communication
technologies.
The rapid development of the IoT puts forward higher technical
requirements for wireless communication technology. LPWAN (low-power Wide-Area
Network) designed for low-bandwidth, low-power, long-distance, and large-scale
IoT applications. ) also quickly emerged. NB-IoT and LoRa are typical
representatives and two of the most promising low-power WAN communication
technologies.
Both LPWANs have the characteristics of wide coverage, many links, low
speed, low cost, and low power consumption. They are suitable for IoT
applications and are actively expanding their ecosystems. But there are
differences between them.
LoRa: Low-power WAN IoT technology that is easy to build and deploy
LoRa was born earlier than NB-IoT. In August 2013, Semtech released a
new chip based on 1Ghz below the Long Range (LoRa) technology. Its acceptance
sensitivity has reached an astonishing -148dbm, and the highest acceptance
sensitivity has improved by more than 20db compared to other advanced sub-Ghz
chips in the industry, which ensures network connection reliability.
It uses linear frequency modulation spread spectrum modulation
technology, which not only maintains the same low power consumption
characteristics like FSK (Frequency Shift Keying) modulation, but also
significantly increases the communication distance, while improving network
efficiency and eliminating interference, that is, different spread spectrum The
terminals of the sequence do not interfere with each other even if they are
transmitted at the same frequency. Therefore, the concentrator/gateway
(Concentrator/Gateway) developed on this basis can receive and process data of
multiple nodes in parallel, greatly expanding the system capacity.
Linear spread spectrum has been used in military and space
communications for decades because it can achieve long communication distances
and robustness of interference, while LoRa is the first to be used for commercial
purposes. With the introduction of LoRa, the situation in the field of embedded
wireless communications has undergone a complete change. This technology
changes the previous trade-offs between transmission distance and power
consumption, providing a simple communication system that can achieve long
distance, long battery life, large capacity, and low cost.
The main advantages of
LoRa:
1. Greatly improved the sensitivity of acceptance and reduced power
consumption
The link budget of up to 157db allows communication distances of up to
15 kilometers (related to the environment). Its receiving current is only 10mA,
and the sleep current is 200nA, which greatly delays the battery life.
2. The gateway/concentrator based on this technology supports parallel processing
of multiple channels and multiple data rates, and the system capacity is large.
If the gateway is installed at the location of the existing mobile
communication base station and the transmission power is 20 dBm (100 mW), it
can cover about 2 km in a densely constructed urban environment, and up to 10
km in a suburb with a lower density.
3. Terminal and concentrator/gateway based systems can support ranging
and positioning.
LoRa's measurement of distance is based on the signal's over-the-air
transmission time rather than the traditional RSSI (Received Signal Strength
Indication), while positioning is based on the multipoint (gateway) measurement
of the air transmission time difference of one point (node). Its positioning
accuracy can reach 5m (assuming a range of 10km).
These key features make LoRa technology ideal for IoT applications that
require low power consumption, long distances, extensive links, and location
tracking, such as smart meter reading, smart parking, vehicle tracking, pet
tracking, smart farming, command industry, smart city Applications and areas of
smart communities, etc.
4. LoRaWAN is a low-power WAN standard based on the open source MAC
layer protocol introduced by the LoRa Alliance. This technology provides a
local, national, or global network for battery-powered wireless devices.
LoRaWAN is aimed at some of the core technology requirements in the Internet of
Things, such as secure two-way communication, certain communications and static
location identification. The technology enables seamless interworking between
smart devices without local complex configuration, giving users, developers,
and enterprises in the Internet of Things free operation rights.
5. The LoRaWAN network architecture is a typical star topology. In this
network architecture, the LoRa gateway is a transparent transmission relay,
linking terminal devices and back-end central servers. The gateway communicates
with the server through a standard IP link, and the terminal device
communicates with one or more gateways using a single hop. All nodes and
gateways are two-way communication, and also support operations such as cloud
upgrade to reduce cloud communication time.
NB-IoT standards and
progress
1. RAN aspect
NB-IoT has evolved from a narrowband technology to a formal standard of
3GPP. The active promotion of relevant manufacturers and operators and the real
needs of the market are two factors that cannot be ignored.
The 3GPP communication technology standards can be mainly divided into
Core Part (subject function), performance standard and RF conformance test
standard. Among them, the main function standard refers to the specific content
of the protocol, including signaling protocol, network access, etc., mainly
related to development; performance standards are mainly the performance of
each sub-technical field, related to test strength; conformance test standard,
mainly Includes test criteria for some processes and functions.
2.SA/CT aspects
In order to meet the massively fragmented, low-cost, low-rate, low-power
NB-IoT IoT applications, the core network mainly considers the following
issues:
(1) Efficient support for infrequent packet transmission
Further improving the processing efficiency of infrequent packet
transmission for NB-IoT. Since the number of NB-IoT terminals may increase
exponentially, the data volume and communication cycle of each terminal are
relatively low, and the existing EPS core network is used to process such
services, and its efficiency will be very low and overloaded. Risk, therefore,
it is necessary to minimize the signaling overhead of the entire EPS system,
especially the air interface portion.
(2) Using a packet to transmit an efficient support tracking device
3GPP does not specifically define the business model of such a service,
and is still in the research state. Its business model belongs to the variant
of the MAR (mobile terminal periodic reporting) business model, which needs to
be further enhanced in terms of positioning, mobility, transmission efficiency
and optimization, etc.
In summary, NB-IoT and LoRa have their own advantages. a network that
brings convenience and convenience to our lives.
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