History

BlueTooth SIG (Special Interest Group) [32] was founded by Ericsson, IBM, Nokia, Intel, and Toshiba in February 1998. The mission of BlueTooth SIG is to develop an open standard for short-range wireless technology called BlueTooth. L. M. Ericsson of Sweden invented BlueTooth technology first in 1994. The first version of specification, BlueTooth V1.0b, is released in December 1999 and the second reversion, BlueTooth V1.1, in February 2001. Moreover, the second version is downward compatible to v1.0b.

2.3.2.2 Overview

BlueTooth is an open standard version of WPAN (Wireless Personal Area Network).

Identical to IEEE 802.11b, BlueTooth v1.x adopts 2.4 GHz as its operation frequency band but it utilizes FHSS (Frequency Hopping Spread Spectrum) as its modulation scheme. However, compared with IEEE 802.11, BlueTooth has different market partition The hopping frequency of BlueTooth is 1600 hops per second, the frequency spectrum is normally divided into 79 channels with 1 MHz channel spacing per channel. The maximum of transmitting distance is up to 10 meter at 0 dBm transmitter RF power and up to 100 meters at 20 dBm.

BlueTooth supports two data transfer modes, one is ACL (Asynchronous Connection-Less) for data packet, and the other is SCO (Synchronous Connection-Oriented) for voice packet. The maximum of data rate of ACL is up to 723.2 kb/s asymmetric (and still up to 57.6 kb/s in the return direction) and up to 433.9 kb/s symmetric.

Figure 2.9: BlueTooth Scatter net Network Topology

The network topology of BlueTooth is a master-slave based Ad-Hoc network. It supports up to 7 slaves with a single master in a piconet organized into groups of two to eight devices, consisting of a single master and one or more slave devices. A device in a piconet may additionally belong to more than one piconet, either as a slave in both or as a master in one piconet and a slave in another. These devices are bridges to connect the different piconets and form the expanded the network topology called scatter net that is shown in Figure 2.9.

Figure 2.10: BlueTooth Protocol Stack

Figure 2.10 is BlueTooth protocol stack, the left of this figure is the One Processor Solution architecture and the right hand side is the Two Processor Solution architecture that means it has another processor as a host (usually called host controller) to control BlueTooth module at the remote side. The Two Processor solution uses the HCI (Host Controller Interface) interface to separate the protocol stack of the One Processor solution into host and remote sides. The HCI provides the uniform interface for different physical bus such as USB, UART, PC Card, etc. In this case, you need to choose the suitable HCI transporter layer standard and implement the HCI transport layer depending on different physical bus. Accordingly, host controller can communicate with BlueTooth module through HCI protocol through certain physical bus.

Each layer of the protocol stack of BlueTooth is very important and its responsibility for different functions. For example, the (Logical Link Control and Adaptation Protocol) L2CAP provides protocol multiplexing which allows different upper protocols, some of them are belong BlueTooth such as RFCOMM which emulate serial port which allows the legacy software can operate on a BlueTooth device, TCS (Telephony Control Protocol Specification) which provides for voice and data call control and SDP (Service Discovery Protocol) which provides a discovery mechanism to discover which BlueTooth specific services is available provided by

nearby BlueTooth devices, and the others are implemented by 3^rd party company such as TCP/IP. The L2CAP layer also provides the fragmentation and reassembly of packets between layers, and negotiation and monitoring QoS (Quality of Service) between devices.

BlueTooth SIG also defines many profiles to ensure the interoperability between products from different companies. In the viewpoint of end user, the profiles ensure the common experience. In the viewpoint of application developer, the profiles specify the combined procedures from many basic standards, and reduce set parameter in basic standards. Each profile will lists the required protocol layers including BlueTooth specified such as base-band, LMP, L2CAP, SDP, RFCOMM, etc.

and 3^rd party specified such as TCP/IP, WAP, etc. Please refer [32][33][34][35] to get more details about BlueTooth technology.

2.3.3 HomeRF

2.3.3.1 History

HomeRF Working Group [36] was formed in 1997. The major members are Compaq, Ericsson, HP, IBM, Microsoft, Motorola, Philips, Proxim, and Symbionics. The main goal of this group is to enable the wireless data and voice networking within the home.

HomeRF v2.0 is released in 2001.

2.3.3.2 Overview

HomeRF compared with the other wireless technologies, such as BlueTooth and IEEE 802.11, is the wireless technology focus on home networking at the consumer price points. HomeRF combined three technologies - IEEE 802.11, OpenAir, and DECT to provide a complete solution for wireless home networking. It integrates the data, voice, and media streaming in home networking. The voice channel is simultaneously up to 8 channels. It also incorporates the DECT (Digital Enhanced Cordless Telephony) standard, and provides a range of up to 150 feet currently. The speed of data rate is 10-20Mbps+ in HomeRF v2.x.

The same as BlueTooth, HomeRF also adopts the FHSS (Frequency. Hopping Spread Spectrum) technology as modulation scheme in 2.4GHz band due to FHSS is more interference immune than DSSS. And it also plans to use Adaptive FH

(Frequency Hopping) to avoid static interference to ensure the peak performance.

The MAC layer of HomeRF utilizes the CSMA/CA for data transferring, and the TDMA (Time Division Multiple Access) for delivery of voice traffic. It will be full compliance with IEEE 802.11a at 54Mbps for 5GHz band in the future version. The future version will be downward compatible with all previous released versions. It also supports the QoS and security. The issue of coexistence of existing wireless standards is also considered in HomeRF.

Chapter 3.

Home System Standards

3.1 Introduction

We have already introduced many home networking interface standards in Chapter 2.

Then we want to give you an overview of the trend of the home system standards in this chapter.

A home system, which can be called “Framework” or “Middleware”, is system architecture to manage the services of the home appliances. Refer to the explanation of the Xilinx White paper [37] - “The home networking middleware is a layer of software that lies on top of an information appliance operating system. It provides

“hook” of APIs to which home networking appliances can be attached”. On the other hand, each home appliance can access services and share resources with each other through home system. Besides, some of home system standards provide the capability of the multimedia service too. In conclusion, the home systems connect with all home appliances and manage all services of those appliances, so end users can access all services and share resources in the home network.

Figure 3.1: Home systems choice in 2002 [38]

In recent year, there are many home system standards, such as OSGi, UPnP, Jini and so on, are proposed and developed the related products around the world. As shown in Figure 3.1, we can see the choices of home systems in 2002. [38] Because there are so many choices of home systems especially in North America, it will confuse us to choose the suitable one. The Europeans have observed the phenomenon and start to combine three competing home systems in Europe into one called Konnex. Besides, HES (Home Electronic System) is an international home system standard, but it is not accomplished yet. The primary objective of HES is to provide a specify hardware and software that enable a manufacture to make only one version of product for connecting with other home networking standards. The more details are introduced in Section 3.3. Moreover, OSGi standard is similar with HES. It proposes a service framework running on the residential gateway to integrate all services provides by home appliances of multiple different home systems. The more details are described in Section 3.2. Furthermore, we introduce some representative home system in the remaining sections.

3.2 OSGi

3.2.1 History

OSGi (Open Service Gateway initiative) was founded in March 1999. There are over 60 members including Ericsson, Cisco, Nokia, Siemens, Sun Microsystems, and IBM.

The fist version, OSGi SPR1, was released in May 2000, and the second version,

OSGi SPR2, in October 20001.

Figure 3.2: OSGi Gateway [44]

3.2.2 Overview

OSGi is a standard to integrate whole home appliances into a residential gateway by services. In Figure 3.2, we can see that OSGi attempts to integrate not only home networking interfaces but also home systems. It provides a open architecture for service providers, service aggregator, service gateway provider, WAN provider, Internet service provider, appliance manufacture, equipment manufacture, and home network system developer [38][42][44]. In other words, it will create a new business model and bring huge market.