WO1997030540A1

WO1997030540A1 - Apparatus and method for protocol interface

Info

Publication number: WO1997030540A1
Application number: PCT/US1997/001797
Authority: WO
Inventors: Jacqueline Mullins; Alan Hendrickson; Paul Schnizlein
Original assignee: Advanced Micro Devices, Inc.
Priority date: 1996-02-15
Filing date: 1997-02-03
Publication date: 1997-08-21

Abstract

An apparatus for digital cordless telecommunications includes a frame formatter for logical channel formatting of transmitted baseband signals and received baseband signals. The apparatus comprises a radio interface connection with the frame formatter, for delivering and receiving the transmitted baseband signal and the received baseband signal, respectively, a FIFO/codec interface connected with the frame formatter, an interrupt interface connected with the frame formatter, a control register interface connected with the frame formatter, and a microcontroller interface connected with the frame formatter.

Description

APPARATUS AND METHOD FOR PROTOCOL INTERFACE

Background of the Invention

The present invention relates to an interface of a telecommunications device and, more particularly, to an interface of a frame formatter of a baseband integrated circuit employable in base set and hand set units of digital cordless telephones.

Telecommunications technology has significantly advanced, particularly in recent decades. Current trends in telecommunications research and development efforts appear to indicate that achieving greater mobility, and maintaining capabilities and quality, will be significant areas of interest in the future of telecommunications technology. One type of telecommunications device that allows for increased mobility over the standard cord-connected telephone is the digital cordless telephone. Digital cordless telephones are generally known, however, design improvements and enhanced operations continue to be attained. Although improvements and advances are being made in telecomπiunications technology which aid in allowing greater mobility, they incidentally may give rise to certain problems and disadvantages. With greater mobility, for example, comes the necessity for better reduction of noise interference, greater power requirements, and increased capabilities in transfer of greater amounts of information over radio frequency (RF) bandwidth and electrical pathways.

As with telecommunications technology, integrated circuit design technology also continues to advance. Efforts are ongoing, for example, to group more and more components on a single integrated circuit or "chip". Many benefits are possible through the grouping of components, such as, for example, smaller size, faster operation, and reduced noise interference. When multiple components are grouped on a single chip, however, suitable pathways for signal communications between the components become difficult to design. This is the case because of the time and space limitations imposed by virtue of the physical constraints of the single chip. Such groupings on a single chip may also exhibit other disadvantages. For example, chip designers must often seek to design chips suitable for varied applications and components, to thereby allow for easy removal or addition of components without the necessity of complete redesign of the entire chip.

The particular design possibilities, pitfalls, and preferences in any instance are greatly multiplied as the number of components on the chip grows, as signal communications and component processing speeds increase, and as more signal data is passed between the various components. The designer's decisions with respect to the many tradeoff possibilities, pitfalls, and preferences are particularly tough for the designer in the case of telecommunications devices, such as, for example, digital cordless telephones. In designing those devices, the multitudes of design choices possible must each be considered to attain suitable designs. Designing for appropriate operations alone, much less optimizing signal communications between components, is a monumental task. Thus, each new design for accomplishing those signal communications may have particular desirable characteristics and advantages.

As with signal communications designs for electronics products generally, signal communication configurations of telecommunications equipment, and, in particular, digital cordless telephones, may exhibit various desired characteristics and advantages according to design. For example, the protocol or "format" of transmitted and received signals, both between communications units and between components of those units, may impact design choices. This is certainly the case where a particular, desirable format is communicated over RF and communications units must appropriately operate to make communications possible through that format. Also, if varied application is intended, the signal communications by the equipment may be preferable in a certain design in comparison to other designs. In any event, the particular operation, application, and service of telecommunications devices, such as digital cordless telephones, are limited only by the designer's capabilities and imagination and the limits of the technology. Due to particular design choices and configurations, embodiments of the present invention present various advantages and improvements, not heretofore realized, in signal communications between components and sub- parts of a telecommunications device, which device may, for example, be a digital cordless telephone. As hereinafter more fully described and better understood, the particular configurations of the components and sub-parts and of the signal communications therebetween provide significant improvements and advances in the art and technology of telecommunications and, particularly, digital cordless telecommunications.

Summary of the Invention

An embodiment of the invention is an apparatus for digital cordless telecommunications. The apparatus includes a frame formatter. The frame formatter provides logical channel formatting of transmitted baseband signals and received baseband signals. The apparatus comprises a radio interface connection with the frame formatter, for delivering and receiving the transmitted baseband signal and the received baseband signal, respectively, a FIFO/codec interface connected with the frame formatter, an interrupt interface connected with the frame formatter, a control register interface connected with the frame formatter, and a microcontroller interface connected with the frame formatter.

Another embodiment of the invention is a method of digital cordless telecommunications, wherein the method includes formatting of transmitted baseband signals and received baseband signals. The method comprises the steps of interfacing with a radio, for delivery and reception of the transmitted baseband signal and the received baseband signal, respectively, interfacing with a codec to decode and encode the received baseband signal and the transmitted baseband signal, respectively, interfacing with an interrupt controller to maintain veracity of the transmitted baseband signal and the received baseband signal, interfacing with a microcontroller to communicate error and control signals to receive the received baseband signal and to transmit the transmitted baseband signal, and interfacing with a microcontroller to ensure operation of the microcontroller conforms operations to receive the received baseband signal and to transmit the transmitted baseband signal.

Brief Description of the Drawings

Fig. 1 is an illustration of a telecommunications system connected with several communications units, including a digital cordless telephone base set unit and hand set unit, each comprising certain embodiments of the present invention;

Fig. 2 is a view of certain elements, in accordance with certain embodiments of the present invention, within a base station unit or hand set unit shown in Fig.1;

Fig. 3 is a block diagram of functional blocks of a baseband chip having an interface according to certain embodiments of the present invention; and

Fig. 4 is an example frame format, according to certain embodiments of the present invention, which frame format may serve for desired transmissions and receptions of communicated information.

Description of the Preferred Embodiments

Referring to Fig. 1, several telecommunications devices are connected to and form a telecommunications network 2. The telecommunications network 2 is typically a PSTN (Public Switched Telephone Network), although an ISDN (Integrated Services Digital Network) may also be an application for the embodiments of the invention. For purposes of example only, the illustration of the telecommunications network 2 shows, in particular, base set units 4 of two cordless telephones wire-linked with other portions of the telecommunications network 2. Each of the base set units 4 has a particular hand set unit 6 with which the base set unit 4 is in radio frequency (RF) communication. Also, for purposes of example, the telecommunications network 2 is shown to include a typical corded telephone 8 and another telecommunications device 10, which may be, for example, a communications device such as a facsimile machine, a modem for a computer, or some other such device. Each of the devices is connected to the telecommunications network 2 by a network link 12, which may, for example, be a wired-link, an optical fiber link, a long-distance radio link, or some other communications link.

Each of the cordless telephone devices of the illustrated embodiment comprises one base set unit 4 and one corresponding hand set unit 6. The base set unit 4 and hand set unit 6 communicate over an RF link 14, so that communications information may be passed between the hand set unit 6 and base set unit 4. The base set unit 4, being tied by the network link 12 with the telecommunications network 2, receives communications from the network 2 and passes communications to the network 2. Because the base set unit 4 and hand set unit 6 are capable of passing communications information back and forth between the units 4, 6, communications from the telecommunications network 2 may be passed to the hand set unit 6 and passed from the hand set unit 6 to the telecommunications network 2, each via the base set unit 4 and the link 12.

Typically, the base set unit 4 of a cordless telephone is virtually immobile, or at most mobile over a very limited range, because of the fixed physical length of the network link 12 to such unit 4. The same is true of the typical corded telephone 8 and other telecommunications device 10 because each is linked to the network 2 by a fixed physical length connector, such as a wire, optical fiber, or other equipment, which serves as the network link 12. In the illustration of Fig. 1, it is of note that in comparison to the corded telephone 8, communications device 10, and base set unit 4, the hand set unit 6 may have much greater mobility. This is so because the hand set unit 6 is mobile with respect to the base set unit 4 and unimpeded by a fixed physical length connector such as the link 12. Instead of such a connector, communications between base set unit 4 and hand set unit 6 occur over the RF link 14. Although there are typically distance limits to capabilities of RF communication over the RF link 14, the RF communications between base set unit 4 and hand set unit 6 over the RF link 14 may generally be accomplished at greater and varied distances between base set unit 4 and hand set unit 6 in comparison to the fixed physical length connector as the network link 12 of other types of devices. Such an RF link 14 between base set unit 4 and hand set unit 6, versus some other physical network link 12, such as a fixed length wire, thus, provides much greater flexibility of use of the hand set unit 6 at varied locations during communications.

Although variations and improvements are continually being made in cordless telephone devices 4, 6, such as those illustrated in Fig. 1, embodiments of the present invention will be applicable to many of those variations and improvements. Certain variations and improvements in the cordless telephone devices 4, 6 could include, for example, multiple hand set units 6 communicating with a single base set unit 4; hand set unit 6 communications capability with any one of a group of base set units 4 capable of such communications, when in the vicinity of a base set unit 4 of the group; office branch exchanges or intercom systems with multiple hand set units 6 communicating with one or more base set units 4; and others. Although the embodiments of the present invention expressly described herein are discussed primarily in reference to a configuration of one base set unit 4 with a network 12 being dedicated to a single hand set unit 6, and vice-versa, the descriptions should not be considered limited to that configuration. As those in the art will readily appreciate, multiple variations, with various advantages and attributes of each, are possible.

Now referring to Fig. 2, a cordless telecommunications unit 20, which may be either a base set unit 4 or a hand set unit 6, includes two main parts. The two parts are a baseband chip 22 and a radio 24. The baseband chip 22 may include a variety of devices, such as various controllers, codecs, formatters, and other functions. The baseband chip 22 may be a single semiconductor chip, some other integrated circuit, or other functional circuitry. The radio 24 may also include various functionality, such as, for example, various oscillators, up and down convertors, synthesizers, and antennas. As with the baseband chip 22, the radio 24 may be a semiconductor device, another integrated circuit, or other circuitry. A particularly desirable cordless telecommunications unit 20 comprises a baseband chip 22 which operates at CMOS-levels and transmits and receives various signals to and from the radio 24 at those levels. The radio 24 of such a desirable unit 20 converts RF signals 14 to and from the CMOS-level baseband signals of the baseband chip 22 to enable RF communications among corresponding hand set and base set units 4, 6.

In embodiments of the present invention, the baseband chip 22 and radio 24 of the unit 20 pass signals, such as a transmit baseband signal 226, a receive baseband signal 228, and a reference clock output 224, each between the other. In addition to those signals 226, 228, 224, various other signals 30 may be passed between the radio 24 and the baseband chip 22 to accomplish a variety of purposes, for example, reset, wake-up, power monitor, interrupt, and a wide variety of other purposes depending upon the interfacing aspects and desired functions of the unit 20.

Although not detailed herein because not necessary to understanding the embodiments of the present invention and generally known to those skilled in the art, the cordless telecommunications unit 20 may be equipped with various peripherals (not shown) in order to allow appropriate usability and desired operations. The peripherals may include, for example, matters such as power, power controls, touch keys, on/off controls, speakers, LCD's, transducers, such as microphones and ear pieces, key scanners, and other peripheral elements. In order to function as a digital cordless telephone, the telecommunications unit 20 must be equipped with a variety of those peripherals and others, as those skilled in the art will know and appreciate.

Referring now to Fig. 3, the reference numeral 22 refers, in general, to the baseband chip 22 of a cordless telecommunications unit 20 (shown in Fig. 2). The functional blocks of the embodiment of the chip 22 are shown in Fig. 3. Generally, the baseband chip 22 includes various elements forming a system control function block 40, an audio function block 42, and a protocol function block 44. These functional blocks 40, 42, 44 of the baseband chip 22 are each particularly interfaced to connect with others of the functional blocks 40, 42, 44 and external elements in desired manners to accomplish desired and preferred communication through use of an optimized frame format (illustrated in Fig. 4, as hereinafter described).

The embodiments of the present invention comprise the interfaces of the protocol function block 44 with the other functional blocks 40, 42 of the chip 22 and with the radio 24 (shown in Fig. 2). Details of the frame formatter 112 and a desirable format 150 will be later discussed. In order to understand the various embodiments of the present invention, it is sufficient merely to understand that the frame formatter 112 formats transmissions and receives appropriately formatted receptions.

In general, there are five primary interfaces to the protocol function block 44. Each of those interfaces is with the frame formatter 112 of the protocol function block 44. The five interfaces are: (1) a radio interface 114, connecting the frame formatter 112 with the radio 24 (shown in Fig. 2) of the telecommunications unit 20 (also shown in Fig. 2); (2) a FIFO/codec interface 128, connecting a FIFO element of the frame formatter 112 with a codec 124 of the audio function block 42; (3) an interrupt interface 146, connecting the frame formatter 112 with an interrupt controller 144 of the system control functions 40 block; (4) a control register interface 147, connecting a control register 125 of the frame formatter 112 with the microcontroller 130; and (5) a microcontroller interface 140, connecting the frame formatter 112 with a microcontroller 130 of the system control functions 40 block. These five interfaces of the frame formatter 112 of the protocol function block 44 enable operations of the baseband chip 22 when a frame format, such as, for example, a multiple logical channel format like the format 150 (shown in Fig. 4, and hereinafter discussed) or some other format of transmitted and received data is employed.

Turning now to discussion of each of the five interfaces 114, 128, 146, 147, 140 in greater detail, particular aspects and characteristics of the interfaces 114, 128, 146, 147, 140, as they operate to enable desirable communications utilizing a frame format, for example, the format 150 shown in Fig. 4, may be better understood. Beginning with discussion of the radio interface 114, the radio interface 114 comprises a transmit

bus 226 and a receive (R _XBΈ bus 228. These buses 226, 228 allow the baseband chip 22 to communicate baseband signals with the radio 24 (shown in Fig. 2) of the cordless telecommunications unit (Fig. 2) The baseband signals may be communicated according to a desirable frame format therefor, such as, for example, the three logical channel format 150 (Fig. 4). The buses 226, 228 may, for example, be configured to operate in a serial manner.

Turning now to the microcontroller interface 140, the microcontroller interface 140 directly connects the microcontroller 130 with certain registers (not shown in detail) of the frame formatter 112. Those registers may be supplied with certain information by the microcontroller, via the microcontroller interface 140. The information maintained in those registers may be used at the frame formatter 112 to control the formatter 112 operation. Software may, for example, cause the microcontroller 130 to write certain values to the registers. Those values, then, control the formatter 112 operations. The values may dictate the start of transmission, the synchronization pattern to be detected, the data to be transmitted over certain logical channels, or other matters at the formatter 112.

In addition to the microcontroller interface 140, the microcontroller 130 and frame formatter 112 also interface through the control register 125 via the control register interface 147. The control register interface 147 provides for passage of control data, for example, D-Channel data 154 (shown in Fig. 4), between the control register 125 of the formatter 112 and the microcontroller 130. Such data may be passed both ways across the interface 147. The D-Channel data 154 comprises many error communication flags, such as cyclic redundancy check (not shown) and parity errors (also not shown). Furthermore, the D-Channel data 154 provides status communication flags, such as receive buffer full (also not shown). These flags are used to control the formatter, and to communicate with the remote unit 20 (Fig. 2). Now addressing the interrupt interface 146, the interrupt interface 146 directly connects an interrupt controller 144 with the frame formatter 112. The frame formatter 112 may pass interrupt signals or status bits to the interrupt controller 144 over the interrupt interface 146. The interrupt signals and status bits passed over the interrupt interface 146 may serve a variety of purposes, as those skilled in the art will know and appreciate. Certain particular reasons those signals and bits may be sent by the formatter 112 to the interrupt controller 144 may include, for example, to indicate conditions of signals at the radio interface 114 or other conditions or matters.

Now referring to the FIFO/codec interface 128, the FIFO/codec interface 128 serves to interface a FIFO element (not shown in detail) of the frame formatter 112 with the codec 124, which, for example, may be an adaptive differential pulse code modulator (ADPCM). The FIFO/codec interface 128 provides for passage of data, for example, B-Channel data 156 (shown in Fig. 4), between the FIFO element of the formatter 112 and the codec 124. Such data may be passed both ways across the interface 128. The FIFO element, in such embodiment, may serve as a buffer between the codec 124 and the frame formatter 112. The FIFO element may also, according to certain embodiments, accept clock timing adjustment information from the frame formatter 112. Based on such information, the FIFO element may enable corrections to the internal clocks generated by the formatter 112. Corrected internal clocks may, for example, be passed over the FIFO/codec interface 128 to the codec 124 and employed to keep the chip 22 synchronized.

Referring to Fig. 4, pursuant to these embodiments of the interfaces 114, 128, 140, 146, 147 of the frame formatter 112 of the baseband chip 22, a multichannel data format, for example, the format 150, may be transmitted and received by the frame formatter 112 in a desired manner. The multichannel data format, for example, the format 150, may comprise several distinct logical channels, such as, in the case of the format 150, three logical channels. In the example format 150, the three logical channels are: a transparent voice B-channel 156, an error- control, packetized control D- channel 154, and a framing synchronization SYN-channel 152. Such a three channel format 150 may be followed in communications between the baseband chip 22 (Figs. 2 and 3) and the radio 24 (Fig. 2) of a cordless telecommunications unit 20 (Fig. 2). That three channel format 150 could also be followed in RF communications units 20, 20' (Fig. 2), such as, for example, the base set unit 4 and the hand set unit 6 of a digital cordless telephone (Fig. 1).

In the case of the particular frame format 150, each such format 150 comprises an initial SYN-channel 152 of data which contains a fixed synchronization pattern (not shown) for timing recovery and frame alignment. The SYN-channel 152 data allows the receiving radio 24 (shown in Fig. 2) to synchronize with the frame formatter 112 during transmission, and the frame formatter 112 to synchronize with the radio 24 during reception. Following the SYN-channel 152, the D-channel 154 and then the B-channel 156 alternate in four subparts each. The D-channel 154 is control data for non- audio, system communications. The B-channel 156 is audio data, such as voice data. There are instances, however, when the B-channel 156 is not used. In those instances, the Tχ_BB bus 226 can run asynchronously, giving added flexibility to the frame formatter 112 and the radio 24 (shown in Fig. 2) to either speed up or slow down the transmission rate.

Now referring to Figs. 1-4, in conjunction, the frame formatter 112 of a unit 20 receives data streams of the form of the frame format 150 and then determines the transmission rate of the received data stream. Once the transmission rate is determined, each of the SYN-channel 152 data packet, the D-channel 154 data packets, and the B-channel 156 data packets are extracted and registered. The frame formatter 112 also delivers data streams of the form of the frame format 150 to the radio 24 of the unit 20 when transmitting to another unit 20'.

The frame formatter 112, through the five interfaces 114, 128, 140, 146, 147, may thereby integrate with the baseband chip 22 and the radio 24 to accomplish desired receptions and transmissions, both of the form of the frame format 150, by the telecommunications unit 20. In particular, the audio interface 128 provides an avenue for the B-channel 156 data received over RF by the unit 20 to pass from the frame formatter 112 to the codec 124 for modulation and also an avenue for the B-channel 156 data encoded at the codec 124 to pass to the frame formatter 112 for formatting and delivery to the radio 24 for RF transmission by the unit 20. As for the microcontroller interface 140 and interrupt interface 146, each provide for complementary activities directed to overall baseband chip 22 control. For example, the D- channel 154 data may be passed over the microcontroller interface 140 from the microcontroller 130 as instructions to the frame formatter 112 for baseband chip 22 transmit and receive operations. The interrupt interface 146, in similar fashion, may serve for passage of interrupt signals from the frame formatter 112 to the interrupt controller 144 upon the existence of conditions at or detected by the frame formatter 112 which dictate changes at the microcontroller 130, such as, for example, software or hardware errors and others. As is apparent from Fig. 3, the interrupt controller 144 and microcontroller 130 are operatively intertwined to provide desired operations of the baseband chip 22. Those skilled in the art will know and appreciate the various possibilities for operations under this and other configurations of those components by virtue of the interfaces 114, 128, 140, 146.

It is to be understood that multiple variations and modifications are possible in the aforementioned embodiments of the invention described herein. Although certain illustrative embodiments of the invention have been shown and described here, a wide range of modification, change, and substitution is contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Accordingly, it is appropriate that the foregoing description be construed broadly and understood as being given by way of illustration and example only, the spirit and scope of the invention being limited only by the appended claims.

Claims

ClaimsWhat is claimed is:

1. An apparatus for digital cordless telecommunications, said apparatus including a frame formatter for logical channel formatting of a transmitted baseband signal and a received baseband signal comprising: a radio interface connected with said frame formatter, for delivering and receiving said transmitted baseband signal and said received baseband signal, respectively; a FIFO/codec interface connected with said frame formatter; a control register interface connected with said frame formatter; an interrupt interface connected with said frame formatter; and a microcontroller interface connected with said frame formatter.

2. A method of digital cordless telecommunications, said method including formatting of a transmitted baseband signal and a received baseband signal, comprising the steps of: interfacing with a radio, for delivery and reception of said transmitted baseband signal and said received baseband signal, respectively; interfacing with a codec to decode and encode said received baseband signal and said transmitted baseband signal, respectively; interfacing with an interrupt controller to maintain veracity of said transmitted baseband signal and said received baseband signal; interfacing with a microcontroller to communicate error and control signals to receive said received baseband signal and to transmit said transmitted baseband signal; and interfacing with a microcontroller to ensure operation of said microcontroller conforms operations to receive said received baseband signal and to transmit said transmitted baseband signal.