U.S. patent application number 09/458573 was filed with the patent office on 2001-08-09 for network protocol-based home entertainment network.
Invention is credited to FRANK, EDWARD H., HOLLOWAY, JOHN T..
Application Number | 20010012338 09/458573 |
Document ID | / |
Family ID | 25503707 |
Filed Date | 2001-08-09 |
United States Patent
Application |
20010012338 |
Kind Code |
A1 |
FRANK, EDWARD H. ; et
al. |
August 9, 2001 |
NETWORK PROTOCOL-BASED HOME ENTERTAINMENT NETWORK
Abstract
An in-home network which includes a telephone line and a
plurality of consumer electronic devices coupled to the telephone
line. Each of the consumer electronic devices is assigned a unique
address, such that each of the consumer electronics devices is
individually addressable via the telephone line. The consumer
electronic devices communicate using a packet-based protocol,
wherein each of the consumer electronic devices transmits analog
signal bursts on telephone line. Each of the consumer electronic
devices can include a wireless signal receiver, such that a first
consumer electronic device can receive control information from a
remote control, and then control the operation of a second consumer
electronic device by transmitting the control information to the
second consumer electronic device via the telephone line.
Inventors: |
FRANK, EDWARD H.; (PORTOLA
VALLEY, CA) ; HOLLOWAY, JOHN T.; (WOODSIDE,
CA) |
Correspondence
Address: |
CHRISTIE PARKER & HALE LLP
P O BOX 7068
PASADENA
CA
911097068
|
Family ID: |
25503707 |
Appl. No.: |
09/458573 |
Filed: |
December 9, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09458573 |
Dec 9, 1999 |
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08960842 |
Oct 30, 1997 |
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6026150 |
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Current U.S.
Class: |
379/90.01 ;
370/445; 379/102.03 |
Current CPC
Class: |
H04L 12/2838 20130101;
H04L 2012/2849 20130101; H04L 2012/2841 20130101; H04L 2012/2845
20130101; H04L 12/2818 20130101; H04L 12/2803 20130101; H04L 12/282
20130101 |
Class at
Publication: |
379/90.01 ;
379/102.03; 370/445; 455/556 |
International
Class: |
H04M 011/00; H04L
012/413; H04M 001/00; H04B 001/38 |
Claims
What is claimed is:
1. An in-home network comprising: a telephone line; and a plurality
of consumer electronic devices coupled to the telephone line,
wherein the consumer electronic devices communicate via a
packet-based protocol over the telephone line.
2. The in-home network of claim 1, wherein the packet-based
protocol enables a transmission rate sufficient to transmit
uncompressed audio or compressed video information on the telephone
line.
3. The in-home network of claim 1, wherein the transmission rate is
at least about 1.5 Mbits per second.
4. The in-home network of claim 1, wherein each of the consumer
electronic devices includes a wireless signal receiver, wherein a
first one of the consumer electronic devices receives a control
signal for controlling a second one of the consumer electronic
devices and transmits the control signal to the second one of the
consumer electronic devices on the telephone line.
5. The network of claim 4, wherein the control signal controls the
on/off status of the second one of the consumer electronic
devices.
6. The network of claim 4, wherein the control signal controls the
volume of the second one of the consumer electronic devices.
7. The network of claim 4, wherein the wireless communication is
infra-red.
8. The network of claim 1, wherein each of the consumer electronic
devices is individually addressable by signals transmitted on the
telephone line.
9. The network of claim 1, wherein the packet-based protocol
comprises the transmission of analog signal burst of discrete
duration on the telephone line.
10. A consumer electronic device comprising: a tuner for receiving
AM, FM or TV broadcast analog signals; an analog to digital
converter coupled to the tuner, wherein the analog to digital
converter converts the analog signal to a digital signal; a modem
coupled to the analog to digital converter, wherein the modem
groups the digital signal into digital packets, and modulates the
digital packets to create analog signal bursts; and a connector for
coupling the modem to a telephone line, such that the analog signal
bursts are provided on the telephone line 11.
11. The consumer electronic device of claim 10, wherein the
consumer electronic device is a television.
12. A consumer electronic device comprising: a modem for receiving
analog signal bursts from a telephone line and converting the
analog signal burst to packet-based information; a processor
coupled to the modem, wherein the processor receives the
packet-based information from the modem, and converts the
packet-based information into a stream of digital audio data; a
digital-to-analog converter coupled to the processor, wherein the
digital-to-analog converter converts the digital audio data into an
analog voltage; and a powered speaker coupled to the
digital-to-analog converter, wherein the powered speaker
acoustically reproduces the analog voltage.
13. A consumer electronic device comprising: a wireless signal
reception circuit for receiving information from a remote control;
a processor coupled to the wireless signal reception circuit,
wherein the processor encapsulates the information into an analog
signal burst and transmits the analog signal burst on a telephone
line.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an in-home network and
protocol for connecting consumer electronic devices. More
specifically, the present invention relates to a network which uses
a telephone line present in the home as a communication channel for
transmitting information in accordance with a network protocol.
[0003] 2. Related Art
[0004] With the advent of the Internet and Internet Protocols (IP),
there is now a standard for how general purpose computers, such as
personal computers, workstations and servers can interchange data
over the telephone system. However, such Internet Protocols have
been limited to computers, and do not facilitate networking within
a consumer's residence.
[0005] In addition to general purpose computers, a consumer's
residence can also include consumer electronics devices. These
consumer electronics devices can include, for example, televisions,
VCRs, DVD players, audio systems (e.g., receivers, amplifiers, CD
players, tape players and speakers), telephones, camcorders and
digital satellite systems (DSS). Some of these devices are designed
to be coupled to one another by dedicated communication channels
during normal operation. For example, televisions, VCRs and DSS are
typically designed to be coupled to one another by coaxial cable.
However, there are particular groups of consumer electronic devices
which are not typically designed to be coupled to one another. For
example, telephones are not typically designed to be coupled to
televisions. It would therefore be desirable to have a network for
operably connecting a wide variety of consumer electronics devices
to a single network within the consumer's residence. It would also
be desirable if such network would facilitate the easy addition of
additional consumer electronic devices.
SUMMARY
[0006] Accordingly, the present invention provides a network which
enables various consumer electronics devices to be operably coupled
to one another using the telephone line present in the consumer's
residence. Each consumer electronic device includes a modem for
communicating on the telephone line.
[0007] In accordance with one embodiment of the invention, a
network protocol is provided for operating the modem within each of
the consumer electronics devices. The network protocol involves
modulating packets of digital information by a transmitter circuit
of the modem, wherein the packets of digital information are
converted into analog signal bursts of discrete duration. These
analog signal bursts are transmitted from the transmitter circuit
to the telephone line. However, no signal is provided from the
transmitter circuit to the telephone line between the analog signal
bursts. As a result, many modems can share the telephone line. The
various modems perform an arbitration function to ensure that only
one modem is transmitting analog signal bursts to the telephone
line at any given time. In one embodiment, a non-idle state signal
is appended to the beginning of the analog signal bursts by the
transmitter circuit, thereby signaling the presence of the analog
signal bursts.
[0008] A receiver circuit of the modem monitors the telephone line
to detect the presence and absence of the analog signal bursts.
This monitoring step is performed by a non-idle detector within the
receiver circuit. When the non-idle detector detects the presence
of the analog signal bursts on the telephone line, the non-idle
detector causes the receiver circuit to demodulate the analog
signal bursts using full processing capabilities of the receiver
circuit. Each analog signal burst includes an address or addresses
of the devices which are to respond to the analog signal burst.
[0009] When the non-idle detector detects the absence of the analog
signal bursts on the telephone line, the non-idle detector disables
the demodulating function of the receiver circuit. This greatly
reduces the processing requirements of the receiver circuit when
there are no analog signal bursts present on the telephone
line.
[0010] In one variation, each of the analog signal bursts includes
a preamble and a corresponding main body. Each preamble is
transmitted in accordance with a predetermined first modem
protocol. However, the main bodies can be transmitted in accordance
with different modem protocols which are different than the first
modem protocol. For example, the different modem protocols may
implement different data rates, modulation formats and/or protocol
versions. The modem protocol associated with each of the main
bodies is identified by information included in the corresponding
preamble. This variation enables devices having different operating
capabilities (e.g., personal computers and televisions) to be
operably coupled to the same telephone line in a multi-drop
configuration.
[0011] The present invention will be more fully understood in view
of the following detailed description taken together with the
drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a block diagram of an in-home network in
accordance with one embodiment of the present invention;
[0013] FIG. 2 is a block diagram of a generic consumer electronic
device for connection to the in-home network of FIG. 1;
[0014] FIG. 3 is a block diagram of a transmitter circuit of a
consumer electronic device of FIG. 2 in accordance with one
embodiment of the invention;
[0015] FIG. 4 is a block diagram of a receiver circuit of a
consumer electronic device of FIG. 2 in accordance with one
embodiment of the invention; and
[0016] FIG. 5 is a schematic representation of packet information
which is transmitted by transmitter circuits in accordance with the
burst-mode protocol of the present embodiment.
DETAILED DESCRIPTION
[0017] FIG. 1 is a block diagram of an in-home network 1 in
accordance with one embodiment of the present invention. In-home
network 1 includes various consumer electronic devices which are
coupled to a common telephone line 2 in the consumer's residence 3.
The telephone line 2, which is a conventional twisted pair
conductor, is also connected to a telephone company central office
4 in a manner well known in the art. The consumer electronic
devices coupled to the telephone line 2 within the consumer's
residence 3 include DSS 10, speakers 11 and 12, television 13,
video-cassette recorder (VCR) 14, personal computer 15, telephone
16, compact-disc (CD) player 17 and tuner 18. The illustrated
consumer electronic devices are intended to be illustrative, but
not limiting. Thus, other types of consumer electronics devices,
such as camcorders, can be coupled to telephone line 2 in
accordance with the principles of the present invention. In-home
network further includes a wireless remote control 20 for
controlling the consumer electronic devices. Each of the consumer
electronic devices 10-18 and remote control 20 operate in
accordance with a network protocol which is described in more
detail below. This network protocol will hereinafter be referred to
as V.IP. Thus, the consumer electronic devices 10-18, which are
designed to operate in accordance with the V.IP protocol can
generically be referred to as V.IP consumer electronic devices.
[0018] As described in more detail below, the V.IP consumer
electronic devices communicate over the telephone line 2 using the
V.IP protocol. The V.IP protocol is a packet-based protocol,
whereby the V.IP consumer electronic devices 10-18 communicate by
transmitting analog signal bursts over the telephone line 2.
[0019] FIG. 2 is a block diagram of a generic V.IP consumer
electronic device 100 in accordance with the present invention.
Thus, the architecture of generic V.IP consumer electronic device
100 can be used to construct any one of the specific consumer
electronic devices 10-18. V.IP consumer electronic device 100 is
coupled to telephone line 2 and 120 volt AC power source 30 as
illustrated. V.IP consumer electronic device 100 includes consumer
electronic circuitry 101, control panel circuitry 102, wireless
receiver circuitry 103, coder/decoder (codec) circuit 104,
processor 105, V.IP modem 106, and RJ11 connector 107. Codec
circuit 104 include analog-to-digital converter (ADC) 111 and
digital-to-analog converter (DAC) 112. V.IP modem 106 includes V.IP
transmitter circuit 114 and V.IP receiver circuit 115.
[0020] Consumer electronic circuitry 101 includes the conventional
circuitry and hardware associated with the particular consumer
electronic device. For example, the consumer electronic circuitry
101 associated with DSS 10 would include a satellite dish and a
set-top box (including the receiver circuitry). For V.IP speaker
11, the consumer electronic circuitry 101 would include
conventional speaker hardware, including a speaker cone, coil and
magnets. V.IP speaker 11 is a powered speaker. Thus, V.IP speaker
11 also includes an amplifier for driving the speaker. For V.IP
television 13, the consumer electronic circuitry 101 would include
a picture tube and conventional control circuitry. Similarly, for
VCR 14, personal computer 15, telephone 16, CD player 17 and tuner
18, the consumer electronic circuitry 101 would include the
conventional circuits and hardware typically associated with these
devices.
[0021] Control panel circuitry 102 includes the conventional front
panel control circuitry associated with the particular consumer
electronic device. That is, control panel circuitry 102 provides a
physical interface for the consumer to control the consumer
electronic device 101. For example, for V.IP speaker 11, the
control panel circuitry 102 would include an on/off switch and
volume control knob for controlling the amplifier within the
powered speaker. For V.IP tuner 18, the control panel circuitry 102
would include, for example, the on/off switch, volume control knob,
balance control levers, equalizer levers, and tuner knob. For the
V.IP personal computer 15, the control panel circuitry 102 would
include, for example, a keyboard or mouse.
[0022] The control panel circuitry 102 is coupled to transmit
control signals to the consumer electronic device 101, thereby
causing the consumer electronic device 101 to be controlled in the
appropriate manner (e.g., change the channel, increase the
volume).
[0023] The wireless receiver 103 is a conventional circuit which
receives wireless control signals (e.g., infra-red signals)
generated by remote control 20. In response to the wireless control
signals, wireless receiver 103 transmits control signals to the
consumer electronic circuitry 101, thereby causing the consumer
electronic circuitry 101 to be controlled in the desired
manner.
[0024] The combination of consumer electronic circuitry 101,
control panel circuitry 102 and wireless receiver 103 form a
conventional consumer electronic device. For example, these three
elements may combine to form a conventional (non-V.IP) television
or a conventional (non-V.IP) speaker. These conventional elements
of consumer electronic device 100 are surrounded by a dashed line
in FIG. 2.
[0025] In accordance with the present invention, control panel
circuitry 102 and wireless receiver 103 are further coupled to
provide control signals to processor 105. As described in more
detail below, processor 105 generates digital packet data in
response to these control signals, and transmits this digital
packet data to V.IP transmitter circuit 114 for further processing.
As described in more detail below, the control signals provided by
front panel circuitry 102 and wireless receiver 103 can be used to
control another one of the V.IP consumer electronic devices.
Conversely, processor 105 can receive digital packet data from V.IP
receiver circuit 115, and in response, control consumer electronic
circuitry 101.
[0026] Consumer electronic device 101 is further coupled to ADC 111
and DAC 112 of codec 104 as illustrated. The purpose of ADC 111 is
to convert analog output signals received from the consumer
electronic circuitry 101 into digital output signals which are
provided to processor 105. The purpose of DAC 112 is to convert
digital signals received from processor 105 into analog signals
which are provided to the consumer electronic circuitry 101. All or
part of codec 104 may not be required, depending upon the nature of
the V.IP consumer electronic device 100. For example, V.IP speaker
11 would not require ADC 111 since a speaker is a device which does
not generate any output analog signals. However, V.IP speaker 11
would use DAC 112 to generate an analog signal for driving the
amplifier of the speaker. V.IP tuner 18 would require ADC 111 since
a tuner is a device which generates analog output signals. V.IP
personal computer 15 would require neither ADC 111 nor DAC 112
since a personal computer generates digital input and output
signals. Thus, the specific requirements of codec 104 are
determined on a case by case basis in view of the operating
characteristics of underlying conventional consumer electronic
device.
[0027] Processor 105 receives digital signals from consumer
electronic circuitry 101, control panel circuitry 102 and wireless
receiver 103, and in response, generates digital data packets for
transmission to V.IP transmitter circuit 114. These digital data
packets can include various information in accordance with the V.IP
protocol. For example, these digital data packets can be
representative of audio or video information transmitted from
consumer electronic circuitry 101, or control information
transmitted from consumer electronic circuitry 101, control panel
circuitry 102 or wireless receiver 103.
[0028] FIG. 3 is a block diagram of V.IP transmitter circuit 114 in
accordance with one embodiment of the invention. V.IP transmitter
circuit 114 includes packet queue 201, framer 202, channel coding
circuit 203, output shaper 204, modulator 205 and digital-to-analog
(D/A) converter 206. In general, V.IP transmitter circuit 114
transforms the digital data packets received from processor 105
into analog burst signals having discrete durations. In accordance
with the V.IP protocol, V.IP transmitter circuit 114 does not
insert idle information between the digital data packets. As a
result, the analog burst signals do not form a continuous signal,
but instead, provide time periods during which other V.IP
transmitter circuits can transmit analog burst signals on telephone
line 2. V.IP transmitter circuit 114 optionally transmits a
predetermined non-idle state signal to indicate that an analog
burst signal is about to be transmitted.
[0029] More specifically, within V.IP transmitter circuit 114, the
digital data packets provided by processor 105 are stored in packet
queue 201. These packets are not synchronous with respect to the
modem bit clock, but arrive at packet queue 201 at random times.
Framer 202 receives the packets from packet queue 201, and in
response, composes discrete bit streams which are synchronous with
respect to the modem bit clock.
[0030] The synchronous bit streams generated by framer 202 are
coded by channel coding circuit 203. Channel coding circuit 203 is
used to compensate for noise and distortion on telephone line 2.
Channel coding circuit 203 provides redundant information (e.g.,
convolutional encoding) to allow for error correction. Channel
coding circuit 203 further performs a scrambling function, as well
as mapping the coded bit streams onto symbol values. The symbol
values generated by channel coding circuit 203 is provided to
output shaper 204.
[0031] Output shaper 204 digitally filters the symbol values
received from channel coding circuit 203. Output shaper circuit 204
limits the frequency bandwidth of these symbol values within a
predetermined range and may also be adjusted to help compensate for
channel distortion. The filtered samples provided by output shaper
204 are provided to modulator 205, which modulates a carrier signal
by the filtered samples. The output of modulator 205 is provided to
D/A converter 206, which generates an analog signal burst for
transmission on telephone line 2.
[0032] The previously described elements of V.IP transmitter
circuit 114 are largely conventional. Thus, the encoding of the
analog signal bursts may be performed in accordance with a
conventional modem protocol, such as xDSL or a voice band modem
protocol. However, a conventional modem transmitter circuit
transmits a continuous analog output signal by inserting idle
information between the digital data packets. Framer 202 typically
inserts this idle information. As previously described, V.IP
transmitter circuit 114 does not insert idle information, thereby
resulting in the generation of analog signal burst of discrete
duration. This is because if V.IP transmitter circuit 114 were to
generate a continuous analog output signal, packet based
communication on telephone line 2 would not be possible.
[0033] The analog signal bursts generated by V.IP transmitter
circuit 114 are routed through RJ11 connector 107 to telephone line
2. In accordance with one embodiment of the invention, the
effective data transmission rate on telephone line 2 is at least
about 1.5 Mbits per second. This enables the transmission of
compressed video and uncompressed audio signals on telephone line
2. The analog signal bursts are transmitted to each of the consumer
electronics devices connected to telephone line 2, as well as,
optionally, to the telephone company central office 4. More
specifically, the analog signal bursts are transmitted to the V.IP
receiver circuits present in each of the consumer electronics
devices connected to telephone line 2.
[0034] FIG. 4 is a block diagram of V.IP receiver circuit 115 in
accordance with one embodiment of the present invention. V.IP
receiver circuit 115 includes A/D converter 301, resampler 302,
equalizer 303, carrier recovery circuit 304, symbol decision
circuit 305, channel decoder 306, framer/idle detector 307, sample
buffer 308, echo canceler 309, timing update circuit 310, equalizer
update circuit 311, carrier update circuit 312, non-idle detector
401 and summing node 319. In combination, carrier recovery circuit
304 and symbol decision circuit 305 form a demodulator. V.IP
receiver circuit 115 is coupled to receive analog signal bursts
which are transmitted on telephone line 2.
[0035] A/D converter 301 samples the analog signal bursts, thereby
converting the analog signal bursts into digital signals. These
digital signals are provided to a positive input terminal of
summing node 319. Echo canceler 309 monitors the analog signal
bursts generated by V.IP transmitter circuit 114 and adaptively
predicts the echo signals on telephone line 2. An echo of the
locally generated analog signals may be present if V.IP modem 106
is operating in full duplex mode. Echo canceler 309 applies the
predicted echo signal to the negative input terminal of summing
node 319, thereby canceling the echo introduced by the local analog
signal bursts generated by transmitter circuit 114.
[0036] The digital signals output by summing node 319 are provided
to conventional resampler 302. Resampler 302 interpolates these
digital signals to generate samples which match the symbol rate of
a V.IP transmitter circuit. Timing update circuit 310 monitors the
digital signals provided by summing node 319. Timing update circuit
310 is a conventional circuit which runs a control loop to extract
symbol timing information from these digital signals. This symbol
timing information is provided to resampler 302, thereby enabling
resampler 302 to control the sampling process as necessary.
[0037] The digital signals output by summing node 319 are further
provided to sample buffer 308. Sample buffer 308 is a dual-port
first-in, first-out (FIFO) circular buffer which stores a most
recent history of the digital signals provided by summing node 319.
In the described embodiment, the information stored in sample
buffer 308 is representative of a plurality of the most recent
symbols.
[0038] The raw input samples are routed from resampler 302 to
adaptive equalizer 303. Adaptive equalizer 303 is a conventional
element which modifies the raw input samples to compensate for
linear distortions introduced by telephone line 2. To accomplish
this, equalizer 303 processes the raw input samples using a
plurality of equalization coefficients which are updated
periodically within equalizer update circuit 311 based on
quantization errors measured at the output of the symbol decision
circuit 305.
[0039] Equalizer 303 provides a stream of equalized digital samples
to carrier recovery circuit 304. Carrier recovery circuit 304 is a
conventional element which extracts the carrier signal from the
equalized digital samples and, for each digital sample, provides a
soft decision (i.e., a best estimate) concerning the identity of
the corresponding symbol. The symbols achieved by the soft decision
are hereinafter referred to as soft symbols. The soft symbols are
transmitted to symbol decision circuit 305.
[0040] Symbol decision circuit 305 is a conventional circuit which
quantizes the soft symbols provided by carrier recovery circuit
304, thereby making a hard decision as to the identity of the
received symbols. The symbols achieved by the hard decision are
hereinafter referred to as hard symbols. The hard symbols are fed
back to equalizer update circuit 311 and carrier update circuit
312. In response, equalizer update circuit 311 and carrier update
circuit 312 determine quantizer error In response to the quantizer
error, equalizer update circuit 311 and carrier update circuit 312
adjust the processing coefficients used by equalizer 303 and
carrier recovery circuit 304, respectively, thereby improving the
accuracy of the hard decisions made by symbol decision circuit
305.
[0041] The hard symbols generated by symbol decision circuit 305
are also provided to conventional channel decoding circuit 306.
Channel decoding circuit 306 uses redundant information in present
in the received analog signal bursts to correct for quantizer
errors. Channel decoding circuit 306 typically implements a maximum
likelihood sequence estimator (MLSE) circuit, such as a Viterbi
decoder, or some other form of error correction. Channel decoding
circuit 306 provides a decoded bit stream to framer 307. Finally,
framer 307 decodes the bit stream into packet-data, discarding the
idle information, and loading the packets of data into packet queue
318.
[0042] In accordance with the V.IP protocol, the analog signal
bursts are immediately preceded by a predetermined signaling on the
communication channel (i.e., a non-idle state signal). This
signaling is selected to be detected by non-idle detector 401
without the computational complexity of full demodulation. Three
such signaling schemes are discussed below.
[0043] First, an easily detected signal, such as a pure tone, can
be used to signal the presence of analog signal bursts (hereinafter
referred to as a DATA state) and the absence of analog signal
bursts (hereinafter referred to as a NO DATA state). In the
described example, the easily detected signal is prefixed to the
onset of the transmission of each analog signal burst. Upon
detecting the easily detected signal, non-idle detector 401 enables
the full processing mode of V.IP receiver circuit 115, thereby
causing V.IP receiver circuit 115 to perform full demodulation on
the incoming analog signal burst. After is the analog signal burst
has been received, non-idle detector 401 detects the absence of the
easily detected signal (and the analog signal burst) on the
communication channel, and in response, enables a reduced
processing mode of V.IP receiver circuit 115. To enable the reduced
processing mode of V.IP receiver circuit 115, non-idle detector 401
disables resampler 302, equalizer 303, carrier recovery circuit
304, symbol decision circuit 305, channel decoder 306, framer/idle
detector 307, echo canceler 309, timing update circuit 310,
equalizer update circuit 311, carrier update circuit 312 and packet
queue 318 of receiver circuit 115, thereby simplifying the modem
function when there is no analog signal burst being received (i.e.,
during the NO DATA state).
[0044] In a second scheme, non-idle detector 401 monitors the
presence and absence of carrier energy on telephone line 2 to
determine whether an analog signal burst is being received. Upon
detecting carrier energy on telephone line 2, non-idle detector 401
enables the full processing mode of V.IP receiver circuit 115. When
no carrier energy (or a minimum carrier energy) is detected on
telephone line 2, non-idle detector 401 enables the reduced
processing mode of V.IP receiver circuit 115.
[0045] In a third scheme, a sub-carrier signal is used to signal
the presence and absence of analog signal bursts. In this
embodiment, the sub-carrier signal is demodulated with much less
computational requirements than the analog signal bursts. One
example of a signaling protocol which uses a sub-carrier signal is
multi-carrier modulation (MCM) signaling. One example of MCM
signaling is Discrete Multi-Tone (DMT) signaling. Although the
receiver circuit used in connection with an MCM signaling protocol
(hereinafter an MCM receiver circuit) uses different circuitry than
V.IP receiver circuit 115, such an MCM receiver circuit is well
known in the art and can be adapted for use with a non-idle
detector in the manner described below.
[0046] In MCM signaling, the received analog signal consists of
multiple sub-channels in the frequency domain. In such a format,
one of these sub-channels is used by the associated transmitter
circuit to signal the presence of the DATA state. A non-idle
detector circuit is coupled to receive the selected sub-channel of
the incoming MCM signal. Upon detecting the sub-channel signaling,
the non-idle detector circuit causes the receiver circuit to enter
into a full processing mode, in which the received analog signal is
processed using the full processing capabilities of the receiver
circuit. After the packet data has been transmitted, the
sub-channel signal is de-asserted. Upon detecting the absence of
the sub-channel signal, the non-idle detector enables a reduced
processing mode within the receiver circuit.
[0047] In the foregoing schemes, V.IP receiver circuit 115 (or the
MCM receiver circuit) operates with a reduced level of processing
to monitor the telephone line 2 to detect the presence of a DATA
state. After a time-out period has expired, telephone line 2 can
automatically be assigned to a call-inactive status, and the
detection processing performed by non-idle detector 401 can be
reduced. The associated V.IP transmitter circuit can then initiate
a session by transmitting a non-idle state signal long enough to
ensure that non-idle detector 401 detects the subsequent DATA
state. Alternatively, V.IP receiver circuit 115 can periodically
poll the other end of the communication channel (i.e., the
associated V.IP transmitter circuit), and only enable non-idle
detector 401 during a window following each poll.
[0048] Alternatively, V.IP receiver circuit 115 can periodically
enable the non-idle detector 401 during predetermined time
intervals which can be used by the remote V.IP transmitter circuit
to signal the transmission of an analog signal burst. A periodic
poll or some other timing signal would be used to maintain
synchronization of these time intervals between V.IP receiver
circuit 115 and the remote V.IP transmitter circuit. In this
manner, the processing requirements of V.IP receiver circuit 115
are further reduced.
[0049] As previously described, when no analog signal burst is
being received, there is a statistically significant reduction in
the amount of processing required within V.IP receiver circuit 115.
This reduction in processing can be used to reduce power
consumption.
[0050] In accordance with another aspect of the invention, the
quality of telephone line 2 can be determined by monitoring various
elements within V.IP receiver circuit 115. For example, error
correction circuitry present in channel decoder 306 can be
monitored to determine the quality of telephone line 2 (i.e.,
whether a large or small amount of error correction is being
performed). Another measure of the signal quality is the mean of
the square of the quantizer error (i.e., the difference between the
input and the output of the symbol decision circuit 305). If
telephone line 2 is determined to be a high quality connection,
then the processing within V.IP receiver circuit 115 can be
reduced. For example, equalizer 303, carrier recovery circuit 304,
timing update circuit 310 and echo canceler 309 can be operated in
a reduced precision processing mode when a high quality telephone
line 2 exists. The processing performed by V.IP receiver circuit
115 in the reduced precision mode in accordance with this variation
is approximately 50 to 25 percent of the processing required in the
full processing mode.
[0051] In a variation of this embodiment, the quality of telephone
line 2 can be determined using higher protocol layers, and the
processing precision of V.IP receiver circuit 115 can be adjusted
accordingly.
[0052] In another variation, echo canceler 309 can monitor the
coefficients used to generate the echo signal. There are typically
a predetermined number of coefficients used to generate the echo
signal. If certain coefficients are small enough to be ignored, the
number of coefficients used to generate the echo signal can be
reduced (with the insignificant coefficients being ignored). As a
result, the processing requirements of echo canceler 309 are
advantageously reduced.
[0053] In accordance with another aspect of the invention, when
using the V.IP protocol, V.IP transmitter circuit 115 will not be
continuously transmitting. During the periods when V.IP transmitter
circuit 115 is not transmitting analog signal bursts, there is no
possibility of an echo signal on telephone line 2. Accordingly,
echo canceler 309 can be disabled when the local V.IP transmitter
circuit 114 is not transmitting analog signal bursts, thereby
further reducing the processing requirements of V.IP receiver
circuit 115.
[0054] The previously described V.IP protocol effectively enables
multi-drop operation. In multi-drop operation, multiple V.IP modems
are connected to the same telephone line 2 using time-division
multiplexing.
[0055] Because the V.IP transmitter circuits in V.IP modems do not
generate IDLE symbols in accordance with the V.IP protocol, these
V.IP transmitter circuits do not introduce any traffic onto
telephone line 2 during the time that the V.IP transmitter circuits
are not transmitting analog signal bursts. As a result, any V.IP
transmitter circuit coupled to telephone line 2 can establish a
session on telephone line 2 as follows.
[0056] First, the V.IP transmitter circuits coupled to telephone
line 2 can transmit analog signal bursts whenever necessary.
However, this may introduce collisions between analog signal bursts
sent by different V.IP transmitter circuits. A better solution is
to use a carrier sense multiple access (CSMA) scheme, where each
V.IP transmitter circuit monitors the telephone line-2 prior to
transmitting an analog signal burst. A common extension to CSMA is
CSMA/CD in which transmissions are immediately terminated if
collisions are detected. Such CSMA schemes are commonly used in the
ethernet field. These CSMA schemes enable effective communication
between a plurality of V.IP modems connected to a single telephone
twisted pair wire (e.g., line 2).
[0057] An alternative to the contention based protocols described
above are a class of schemes commonly referred to as reservation
based protocols. Applying these well known techniques, multiple
V.IP modems use a separate arbitration channel to decide which
modem gains access to the telephone line 2.
[0058] In an alternative embodiment, multi-drop access is provided
by implementing well known ,time division multiple access (TDMA)
techniques in which every V.IP transmitter circuit is assigned a
fixed time slot during which to transmit analog signal bursts. The
advantage of this scheme is ease of implementation. In yet other
embodiments, multi-drop access is provided by implementing
conventional frequency division multiple access (FDMA) schemes,
code division multiple access (CDMA) arbitration schemes, or data
sense multiple access (DSMA) schemes.
[0059] FIG. 5 is a schematic representation of analog signal bursts
700 and 710 which are transmitted by V.IP transmitter circuits in
accordance with one embodiment of the present invention. In the
described example, it is assumed that analog signal burst 700 is
transmitted by a first V.IP transmitter circuit, and the analog
signal burst 710 is transmitted by a second V.IP transmitter
circuit. That is, analog signal burst 700 can be transmitted by any
one of the consumer electronic devices 10-18 (FIG. 1). Analog
signal burst 700 includes a preamble 701 and a main body 702.
Analog signal burst 700 is transmitted using a gated modulation or
gated carrier signal. Preamble 701, which is approximately 20 to
100 symbols in length, includes information identifying the nature
of the packet 700. For example, preamble 701 can include
information which identifies: (1) a version or type field for the
preamble, (2) source and destination addresses associated with the
analog burst signal, (3) the line code (i.e., the modem protocol
being used), (4) the data rate, (5) error control parameters, (6)
length of the analog signal burst and (7) a timing value for the
expected reception slot of a subsequent analog signal burst.
[0060] The V.IP receiver circuits in consumer electronics devices
10-18 detect the information present in the preamble 701 and
establish synchronization at the beginning of the analog signal
burst 700. In the described embodiment, all preambles are
transmitted at a relatively low, common transmission rate. The
preamble 701 contains information which identifies the data rate of
the main body 702 of the analog signal burst. For example, the
preamble 701 may indicate that the main body 702 of the analog
signal burst 700 includes data which is being transmitted at a
higher data rate than the preamble. The V.IP transmitter circuit
then transmits the main body 702 of the analog signal burst 700 at
this higher rate. The V.IP receiver circuit identified by the
destination address of preamble 701 then receives the main body 702
of the analog signal burst 700 at the rate identified in the
preamble 701.
[0061] Returning to FIG. 5, analog signal burst 710 is
representative of an analog signal burst transmitted by a second
V.IP transmitter circuit. Analog signal burst 710 includes preamble
711 and main body 712. Preamble 711 includes information which is
transmitted at the same rate as the information of preamble 701.
However, preamble 711 indicates that the main body 712 is
transmitted at a second data rate, which is different from the data
rate of the main body 702 of analog signal burst 700.
[0062] Because the V.IP receiver circuits are informed of these
different data rates prior to receiving main body 702 and main body
712, the V.IP receiver circuits are able to adjust for these
different data rates. More specifically, preamble 711 can be used
to select a different set of update coefficients for use within the
associated V.IP receiver circuit to process main body 712.
[0063] The previously described rate adaptive protocol allows both
simple devices (which communicate at a relatively low speed) and
complex devices (which communicate at a relatively high speed) to
be operably coupled to a single telephone line at the same
time.
[0064] Because the preamble of each analog signal burst includes
the destination address of the analog signal burst, each V.IP
receiver circuit can monitor the destination address of each analog
signal burst, and in response, filter the analog signal bursts
which do not need to be demodulated, thereby reducing the
processing requirements of the V.IP receiver circuits. In addition,
because the preamble of each analog signal burst includes a source
address, the V.IP receiver circuits can recall appropriate stored
configuration parameters specific to the source in order to speed
the acquisition/demodulation of the analog signal burst.
[0065] As previously described, the preamble can also contain error
control information that will be used by the main body of the
analog signal burst. Using this scheme, the same V.IP modem can
accommodate both "expensive" error control schemes such as might be
required for video applications, as well as "inexpensive" error
control schemes which might be used for traditional packet-based
traffic. Another portion of the error control information can be
used to "request an acknowledgment" from the V.IP receiver circuit.
If the received analog signal burst is acceptable, then the V.IP
receiver circuit will cause an acknowledge (ack) signal to be
transmitted to the V.IP modem residing at the source address. If
the received analog signal burst is not acceptable, then the V.IP
receiver circuit will cause a no acknowledge (nack) signal to be
transmitted to the V.IP modem residing at the source address.
[0066] Examples of operating the in-home network 1 will now be
provided. As previously described, the V.IP protocol transmits
analog signal bursts having source and destination addresses. Thus,
each of the consumer electronic devices 10-18 must be assigned a
network address. These network addresses can be pre-assigned during
manufacture of the consumer electronic device or can be assigned
using a conventional dynamic host configuration protocol (DHCP)
with a DHCP server as known by one of ordinary skill in the art
(e.g., with personal computer 15, or by central office 4).
[0067] After the network addresses have been assigned, any one of
the consumer electronic devices 10-18 can communicate with any
other of the consumer electronic devices 10-18 over telephone line
2 by appropriately addressing the analog signal burst. Thus, V.IP
DSS 10 can transmit analog signal bursts which include video and
audio information to V.IP television 13 and/or V.IP VCR 14 by
including the network addresses of these elements in the preamble
of the analog signal bursts. Similarly, V.IP DSS 10 can transmit
analog signal bursts which include audio information to V.IP
speakers 11 and 12. The analog signal bursts can be broadcast to a
plurality of consumer electronic devices or uni-cast to a single
one of the consumer electronic devices by selecting the destination
addresses.
[0068] In another example, V.IP telephone 16 can transmit analog
signal bursts which contain control information to V.IP television
13. This control information can cause V.IP television 13 to "turn
off" or "turn down the volume" while the consumer is engaging in a
telephone call. This control information can be generated in
response to the consumer's entries on the control panel circuitry
102, or in response to wireless control signals received by
wireless receiver circuit 103 from V.IP remote control 20. V.IP
telephone 16 can also transmit analog signal bursts which contain
audio information to V.IP speakers 11 and 12, thereby broadcasting
a telephone call over these speakers. Again, the transmission of
such audio information can be controlled by the consumer's entries
via the control panel circuitry 103, or in response to wireless
control signals received by wireless receiver circuit 103 from V.IP
remote control.
[0069] In another example, V.IP tuner 18 (or V.IP CD player 17)
transmits analog signal bursts containing audio information to V.IP
speakers 11 and 12. The V.IP speakers 11 and 12 can be addressed in
a manner which results in the creation of various audio effects
(e.g., stereo, surround sound). The V.IP speakers 11 and 12 can
also perform blending in response to time stamp information
included in the analog signal bursts. For example, a middle speaker
can blend audio information addressed to left and right speakers to
create audio information for a center channel.
[0070] The V.IP speakers 11 and 12 can also receive control
information, such as on/off and volume control, from the various
consumer electronic devices via the telephone line 2. Moreover,
V.IP speaker 11 can receive control information from the V.IP
remote control 20. This control information is received by the
wireless receiver 103 within the V.IP speaker 11. Wireless receiver
103 transmits this control information to processor 105. Processor
105, in turn, transmits the control information through V.IP
transmitter circuit 114 and onto telephone line 2 as an analog
signal burst in the manner previously described. This analog signal
burst includes the address of the consumer electronic device to be
controlled. For example, the analog signal burst can include the
address of V.IP tuner 18, and control the V.IP tuner 18 to reduce
its volume or turn on or off. In this manner, consumer electronic
devices which are outside the range of V.IP remote control 20 can
be effectively controlled by V.IP remote control 20, as long as one
of the consumer electronic devices is within the range of V.IP
remote control 20.
[0071] Although the invention has been described in connection with
several embodiments, it is understood that this invention is not
limited to the embodiments disclosed, but is capable of various
modifications which would be apparent to one of ordinary skill in
the art. For example, although the present modems have been
described in terms of particular consumer electronic devices, it is
understood that other consumer electronic devices can be modified
to implement the V.IP protocol in accordance with the present
invention. Moreover, particular components, such as signal
processors and effects generators, can be modified to implement the
V.IP protocol. Thus, the invention is limited only by the following
claims.
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