BLUETOOTH LOW ENERGY Kieon Seong

Introduction  Chap 1. What is Bluetooth Low Energy? Difference Between Classic Bluetooth Device Types Design Goals  Chap 2. Basic Concepts of Bluetooth Low Energy Time and Memory Asymmetric Design Architectures

What is Bluetooth Low Energy Bluetooth low energy is a complementary technology of classic Bluetooth and lowest power consuming wireless technology

Classic Bluetooth Designed to unite the separate worlds of computing and communications Faster and faster radios have been added to the Bluetooth

Bluetooth Low Energy Instead of increasing the data rates, optimized for ultra low power consumption Deployed in extremely high volumes, in order to achieve high volumes low cost is important issue

Three key elements for very low cost  ISM(Industrial, Scientific and Medical) Band Poor propagation characteristics No license required Limiting the power output of devices  IP License Bluetooth Special Interest Group(SIG) has very low license costs compared to other SIG or association that has a FRAND(Fair, Reasonable, and Non-Discriminatory)  Low Power Reduce the materials required to make a device, materials such as batteries Using button-cell batteries. High data rates, large data transfer is not plausible

Device Types

Design Goals  Ultra low power consumption Physical layer : the radio can use less power when transmitting and receiving data Link layer : rapid reconnections and efficient broadcast of data so connections may not be needed Host : reduce the time required once a link layer connection has been made until the application data can be sent

Design Goals  Worldwide operation A worldwide wireless band, 2.45Hz band  Low cost Keep the system small and efficient  Short range Personal area network

Design Goals  Robustness Adaptive frequency hopping A device can hop over a reduced set of frequencies, this avoid the frequencies that other non-adaptive technologies are using Cyclic redundancy check A value to ensure that there are no bit errors in the received packet

Time and Memory  Time is energy Important to reduce the time required to do anything useful Discovering devices Connecting to devices Sending data  Memory Dynamic refreshing requires energy Reduce the amount of memory that is required in every layer

Asymmetric Design Link Layer Attribute Protocol Layer ClientServer Sends requests to the server for data, analyze data, utilize data Simple processing Transmits packets Manage the piconet timing, adaptive frequency hopping set, encryption,and number of other complex procedures Receives the advertiser’s packets Slave Master Scanner Advertiser Holds data

Client-Server Architecture  Problem of connecting devices to the Internet IP stacks takes more memory and energy than is desirable  Smart gateways allow the interconnection between the Internet and very efficient low energy slaves

Service-Oriented Architecture  A collection of services. These services communicate with each other.  Composed of discrete software agents (service provider, service consumer) that have simple, well defined interfaces and are orchestrated through a loose coupling to perform a required function

Rules and conventions for SOA  Formal Contract A formal description of both its exposed functionality and how it behaves

Rules and conventions for SOA  Loose Coupling Reducing the dependencies to a minimum separation between the implementation and its formal contract or its other implementation

Rules and conventions for SOA  Abstraction Less knowledge that client has about how service is provided, the better it is  Reusability Applied to multiple different application  Statelessness Removes all the state from the interaction between the client and the server

Rules and conventions for SOA  Composability Encourages the aggregation of smaller services to enable higher service interface Courier Company Taxi Company

Rules and conventions for SOA  Autonomy Stand alone and perform its task, regardless of what is going on around it

Rules and conventions for SOA  Discoverability Services to be used, they must be discoverable Typically uses separate protocol from interacting with the service but Bluetooth low energy uses a single protocol, the Attribute Protocol