Pulse or digital communications – Spread spectrum – Frequency hopping
Reexamination Certificate
2000-12-11
2004-12-07
Chin, Stephen (Department: 2634)
Pulse or digital communications
Spread spectrum
Frequency hopping
C375S132000
Reexamination Certificate
active
06829288
ABSTRACT:
FIELD OF THE INVENTION
This invention relates, generally, to the field of telecommunications/mobile terminals and, more particularly, it relates to the development of an architecture which allows mobile (wireless) terminals and the like to communicate and coexist independent of the protocol version.
BACKGROUND OF THE INVENTION
Increasingly, companies, corporations, organizations or associations and the like and even individuals are finding more and more that wireless communication is becoming an indispensable addition to the more traditional wired versions to satisfy the needs for mobility, relocation, ad hoc networking, and coverage of locations difficult to wire. Recently, a new technology has been developing which can expand the use of mobile (portable) phones and related hand-held mobile terminals using the same ISM (industrial, scientific and medical) band as that employed by the wireless LAN (local area network) communication which conforms to the IEEE 802.11 standard. This new technology is known as the Bluetooth wireless technology which is a low-powered radio technology which allows users to make effortlessly, wireless and instant connections between various communication devices, such as mobile (wireless) phones and desktop and notebook computers and the like. A communication linkup operating under the Bluetooth system, such as based on the standard dated Nov. 29, 1999, operates on the unlicensed (free) 2.4 GHz ISM frequency band. In the vast majority of countries (including USA, Europe and most other countries) this frequency band actually is 2400-2483.5 MHz. The Bluetooth special interest group (SIG), which is a consortium of leading companies in the related industries, has launched a campaign to achieve total harmonization of the frequency band.
The sophisticated mode of transmission adopted in the Bluetooth specification ensures protection from interference and security of data. A frequency hop transceiver is applied to combat interference and fading. A shaped, binary FM modulation is applied to minimize transceiver complexity. The symbol rate is 1 Ms/s. A slotted channel is applied with a nominal slot length of 625 &mgr;s. For full duplex transmission, the time-division duplex (TDD) scheme is employed. With regard to channel linkup, information is exchanged through packets. Each packet is transmitted on a different hop frequency.
The Bluetooth protocol uses a combination of circuit and packet switching. Slots can be reserved for synchronous packets (e.g., voice traffic). Bluetooth can support an asynchronous data channel, up to three simultaneous synchronous voice channels or a channel which simultaneously supports asynchronous data as well as synchronous voice. Asynchronous data traffic corresponds to an ACL (asychronous connection-less) link while sychronous traffic is associated with voice traffic and is supported by an SCO (synchronous connection-oriented) link.
The Bluetooth specification has two power levels defined, namely, a lower power level that generally covers the small surroundings such as within a room, and a higher power level that can cover a medium range, such as within a home. That is, conventionally, software controls and identity coding built into each microchip ensure that only those units preset by their owners can communicate.
Wireless devices which conform to Bluetooth technology are supported by a Bluetooth system, such as
10
shown in
FIG. 1
of the drawings, consisting of a radio unit
11
, a link control unit
12
, and a support unit for link management and host terminal interface functions
13
. The link controller (LC) in the Bluetooth system (also referred to as the baseband section) describes the specifications of the digital signal processing portion of the hardware, that is, the Bluetooth link controller carries out the baseband protocols and other low-level link routines. As to the link manager (LM), it is a software entity which carriers out link setup, authentication, link configuration and other protocols. The link manager discovers other remote LMs and communicates with them via the link manager protocol (LMP). Details regarding the servicing by a link controller and link manager have been standardized by the Bluetooth SIG.
Software interoperability begins with the Bluetooth link level protocol responsible to the protocol multiplexing, device and service discovery and segmentation and reassembly. Bluetooth devices must be able to recognize each other and load the appropriate software to discover the high level abilities each device supports. This is all supported by Bluetooth software framework. Interoperability at the application requires identical protocol stacks. Different classes of Bluetooth devices including (although not limited thereto) PCs, hand-helds, PDAs (personal digital assistants), headsets, mobile/cellular phones have different compliance requirements. For example, you would not expect a Bluetooth headset to contain an address book. Headsets compliance implies Bluetooth radio compliance, audio capability, and device discovery protocols. More functionality would be expected from cellular phones, hand-held or notebook computers. In order to achieve this interoperability, the Bluetooth software framework employs a complete protocol stack which comprises both Bluetooth specification protocols like LMP and L2CAP (logical link control and adaptation protocol) and non-Bluetooth-specific protocols like OBEX (object exchange protocol) and UDP (user datagram protocol), etc. In designing the protocols and the whole protocol stack, according to the present Bluetooth standard, the main principle has been to maximize the re-use of existing protocols for different purposes at the higher level, instead of “re-inventing the wheel” once again. Thus, the open specification afforded by the Bluetooth protocol stack permits the development of a large number of new applications that take full advantage of the capabilities of the Bluetooth technology.
The Bluetooth system provides a point-to-point wireless connection, in which two Bluetooth units are involved.
FIG. 2A
of the drawings illustrates a point-to-point linkup involving wireless device BT
M
, which has taken the role of the master, and wireless device BT
S
, which is the slave in this connection. Other types of connections, which may be referred to as WPANs (wireless personal area networks) can also be effected under the support of a Bluetooth system. For example,
FIG. 2B
shows a point-to-multipoint connection
21
in which the channel is shared among several Bluetooth units. In this example, wireless device BT
M
represents the master unit and devices BT
S1
-BT
S7
represent the slave units, which are linked to the channel access code set by the master device.
In an ad hoc or WPAN linkup scheme such as shown in
FIG. 2B
, in which two or more units share the same channel, the ad hoc network is referred to as a piconet. A piconet may begin with two connected devices, such as a portable PC (Personal Computer) and a cellular phone, and may grow to eight connected devices, which device may also be identical. However, once a piconet is formed, one unit will act as a master and the remainder as the slaves for the duration of the piconet connection. It should be noted, at present, a piconet is limited to seven slaves. However, many more slaves are able to remain locked to the master of the piconet in a so-called parked state. These parked slaves cannot be active on the channel but may remain synchronized to the master. Both for active and parked slaves, the channel access is controlled by the master.
Multiple piconets with overlapping coverage areas form a scatternet. In this situation, each piconet can only have a single master. However, slaves are able to participate in different piconets on a time-division multiplex basis. In addition, a master in one piconet can be a slave in another piconet. The piconets shall not be time- or frequency-synchronized. Each piconet has its own hopping channel.
FIG. 2C
of the drawings is an example of a scatternet
22
involving overla
Antonelli Terry Stout & Kraus LLP
Chin Stephen
Nokia Corporation
Wang Ted
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