Bluetooth Low Enegy (BLE™)

IEEE 802.15.4 “Low Rate WPAN” (BLE) is designed for low data rate applications to efficiently manage battery consumption. This allows battery powered sensors in a Smart Home to operate for months or even years depending on their period of activity. It is a low complexity wireless standard with specifications also on both Layer 1 (PHY) and Layer 2 (MAC). BLE is highly adopted and an anticipated solution for connecting IoT devices. The restriction of the data communication topology at point-to-point, limited range of communications, and the lack of IP support make it less attractive for Internet of Things applications.

BLE Mesh Protocols

• The Bluetooth Special Interest Group SIG standardized the Internet Protocol Support Profile “IPSP” with IPv6 support between devices over Bluetooth Low Energy “6LowPan”. The next problem arises due to the short range and restricted topology in BLE. A mesh networking protocol for multi-hop support is needed to overcome these limitations.

• SIG formed a Bluetooth Smart Mesh Working Group in February 2015 which joined with Cambridge Silicon Radio “CSR” to create a global standard for Bluetooth Smart mesh. The working group officially adopted profiles in 2016 and introduced “CSRmesh”. This is a flood mesh protocol that utilizes the non connectible advertisements in BLE for transmitting data to individual devices, groups, sub-groups, or all devices.

  CSRmesh uses the simple mechanisms of flood mesh and can communicate on a scale of up to 64,000 devices or groups per network. The flood mesh routing protocol does not need to maintain a routing table which gives CSRmesh a setup time close to zero.

  To support a mesh topology in BLE, CSRmesh chose a multi-layered approach built on top of BLE. This reduces the size of data payload per individual broadcasts. CSRmesh is not an open protocol. The specifications for this protocol show that it uses flood routing methods to connect BLE devices.



• NS-T® developers introduced “NS-Tmesh™”. NS-Tmesh™ benefits from opportunistic routing. NS-Tmesh™ results show that opportunistic flooding has higher efficiency. The experiments demonstrated that if any intermediate node receives a packet sent by a source, it is captured. The probability of at least one node receiving the packet is 0.79, thus, approximately 1.27 broadcasts are required for the packet to reach any of the intermediate nodes. Adding the additional broadcasts performed to the packet transmission from the intermediate nodes to the destination node, 2.27 broadcasts in total are needed. Using a flood routing protocol, the source node similarly has 1.27 packet broadcasts, however the broadcasts from the three intermediate nodes total up to 1.2. The sum of the two broadcasts adds up to 2.47 proving that opportunistic flooding produces optimal results.





NS-T® has designed a low energy solution to help balance network traffic by managing low bandwidth exchanges between “6LowPan” enabled devices over a separate channel. BLE support packages can be configured with newer versions of Linux above “kernel 3.17”. “OpenWrt” provides the basic support packages for enabling “6LowPan”. Once the BLE packages are enabled on a router, the system can be optimized to dynamically switching between BLE and WiFi for low and high Bandwidth communications depending on the energy source. An added function to this feature is the given ability to provide networking during a power outage and serving in regions with nonstable power sources (ie. villages) by adjusting the bandwidth respective to energy efficiency. This improve's connectivity in Smart Homes™ NS-T® implements this feature on compatible devices.

#NS-T for BLE