U.S. patent application number 10/002261 was filed with the patent office on 2002-05-23 for method and apparatus for providing a broadband, wireless, communications network.
This patent application is currently assigned to Sarnoff Corporation. Invention is credited to Malkemes, Robert Conrad, Miiller, Henry Sedwick.
Application Number | 20020061024 10/002261 |
Document ID | / |
Family ID | 27394900 |
Filed Date | 2002-05-23 |
United States Patent
Application |
20020061024 |
Kind Code |
A1 |
Malkemes, Robert Conrad ; et
al. |
May 23, 2002 |
Method and apparatus for providing a broadband, wireless,
communications network
Abstract
Method and apparatus for providing a broadband, wireless network
comprising a neighborhood communications gateway that accepts all
incoming communications signals and securely broadcasts those
signals throughout a neighborhood of residences. Each
communications appliance within the neighborhood is outfitted with
a receiver that decodes the broadcast signals and couples the
signals to the input terminals of the associated communications
appliance. The system is completely "plug-and-play" such that a
user can quickly and easily utilize the gateway for many
communications appliances.
Inventors: |
Malkemes, Robert Conrad;
(Bricktown, NJ) ; Miiller, Henry Sedwick;
(Yardley, PA) |
Correspondence
Address: |
MOSER, PATTERSON & SHERIDAN, LLP
/SARNOFF CORPORATION
595 SHREWSBURY AVENUE
SUITE 100
SHREWSBURY
NJ
07702
US
|
Assignee: |
Sarnoff Corporation
|
Family ID: |
27394900 |
Appl. No.: |
10/002261 |
Filed: |
November 15, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10002261 |
Nov 15, 2001 |
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09772505 |
Jan 30, 2001 |
|
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60206133 |
May 22, 2000 |
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60259834 |
Jan 5, 2001 |
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Current U.S.
Class: |
370/401 ;
370/338 |
Current CPC
Class: |
H04L 1/0041 20130101;
H04B 7/0845 20130101; H04L 1/0068 20130101; H04L 1/06 20130101;
H04L 1/0071 20130101 |
Class at
Publication: |
370/401 ;
370/338 |
International
Class: |
H04L 012/28; H04L
012/56 |
Claims
What is claimed is:
1. Apparatus for providing a wireless wide area network for a
neighborhood of residences comprising: a neighborhood gateway for
receiving a plurality of signals, selecting specific signals from
said plurality of signals and transmitting the selected signals
through an antenna; and a plurality of receivers for receiving said
transmitted signals, where at least one receiver is located in a
residence and each of the receiver converts the transmitted signal
into a format that is compatible with a network appliance.
2. The apparatus of claim 1 wherein said plurality of signals
comprise one or more signals selected from a group comprising
analog cable television, digital cable television, plain old
telephone signals, Digital Subscriber Line signals, satellite
television signals, over-the-air television signals and any
combination thereof.
3. The apparatus of claim 1 further comprising a transmitter
coupled to said network appliance for transmitting a signal
selection signal to said gateway.
4. The apparatus of claim 1 wherein said gateway comprises a
transceiver for transmitting said selected signals and for
receiving control signals from said network appliances.
5. The apparatus of claim 1 wherein said receiver comprises at
least two antennas.
6. The apparatus of claim 5 wherein said receiver further comprises
a spatial diversity combiner coupled to said at least two
antennas.
7. The apparatus of claim 4 wherein said transceiver comprises a
spatial diversity combiner and a plurality of antennas.
8. The apparatus of claim 5 wherein said receiver comprises: a
tuner coupled to each antenna; an analog-to-digital converter
coupled to each tuner; a timing recovery circuit coupled to each
analog to digital converter; a spatial equalizer for each digitized
signal; a combiner for combining the output signals from each of
the spatial equalizers; a temporal equalizer for supressing
inter-symbol interference from the combined signal; a symbol
sampler for sampling the symbols; a tap controller for adjusting
the tap weights of the spatial equalizers and the temporal
equalizers.
9. The apparatus of claim 7 further comprising an appliance
specific processor for processing the symbols to form an appliance
compliant signal.
10. The apparatus of claim 1 wherein said gateway transmits signals
in the 5.725 to 5.825 GHz band.
11. The apparatus of claim 1 wherein said gateway transmits 20 to
40 Mbits/sec in 6 MHz channels.
12. The apparatus of claim 11 wherein said gateway is capable of
transmitting approximately 50 channels.
13. The apparatus of claim 3 wherein said transmitter produces
signals in the 5.15 to 5.25 GHz band.
14. The apparatus of claim 3 wherein said transmitter produces QPSK
modulated signals.
15. The apparatus of claim 1 wherein said gateway transmits 256-ary
signals.
16. A neighborhood gateway for providing a wireless wide area
network across a neighborhood of residences comprising: a plurality
of tuner modules; a plurality of demodulators coupled to said tuner
modules; at least one decoder coupled to said plurality of
demodulators; a transmitter portion for modulating and transmitting
a forward signal; and a receiver portion coupled to a gateway
firewall for receiving commands from a network appliance to request
one of said plurality of tuner modules to select a particular
channel for transmission as a forward signal.
17. The apparatus of claim 16 wherein said plurality of tuner
modules comprise one or more of the following tuners: a VHF tuner;
a UHF tuner; a cable channel tuner; and a DSB tuner.
18. The apparatus of claim 16 further comprising: a reconfigurable
ATM adaptation level 2 circuit coupled to an xDSL stream and to
said gateway firewall.
19. The apparatus of claim 16 wherein said transmitter portion
comprises: an encoder; an M-ary modulator; and a transmitter.
20. The apparatus of claim 19 wherein said M-ary modulator is a
256-ary modulator.
21. The apparatus of claim 16 wherein said receiver is a QPSK
receiver.
22. A method of providing a wireless wide area network for a
neighborhood of users comprising: receiving a channel selection
signal from a network appliance; selecting a channel of information
from a plurality of channels in response to said channel selection
signal; demodulating and decoding a signal in said selected
channel; encoding and modulating said signal to produce an M-ary
signal; and transmitting said M-ary signal to said network
appliance.
23. The method of claim 22 further comprising: receiving said M-ary
signal at said network appliance; and demodulating and decoding
said M-ary signal to display information to a user.
24. The method of claim 23 wherein said M-ary signal receiving step
further comprises: receiving said M-ary signal at a plurality of
antennas; and diversity combining said M-ary signals received by
each antenna.
Description
[0001] This application is a continuation-in-part application of
U.S. patent application Ser. No. 09/772,505, filed Jan. 30, 2001,
which claims benefit of U.S. provisional patent applications
60/206,133, filed May 22, 2000, and 60/259,834, filed Jan. 5,
2001.
[0002] The invention relates to wireless communications networks
and, more particularly, the invention relates to broadband,
wireless communications networks for residential and enterprise
use.
BACKGROUND OF THE DISCLOSURE
[0003] Residences are presently coupled to many sources of
audio/visual entertainment, communications, and computing signals,
including, computer modems, cable television feeds, satellite
television feeds, telephone, over-the-air television and so on.
Each of these sources of signals enters a residence and is routed
via cables, or wires, or phone lines, to an associated
communications appliance, i.e., the telephone signals are routed
through the home on a twisted-pair cable to a telephone, the cable
television signals are routed through the home on a coaxial cable
to a cable set top box, and so on. As such, a residence will have
many cables, wires and other communications connections throughout
the home. Each time an appliance is to be moved from one location
to another, the signal cabling must be rerouted. Such cutting and
splicing leads to noisy connections and signal degradation that
severely effects the fidelity of the signal.
[0004] To remedy this problem, wireless local area networks (LAN)
have been developed that implement the Institute of Electrical and
Electronic Engineers (IEEE) standard 802.11a, 802.11b, and other
variants of the basic 802.11 standard. The 802.11a standard
defines, for example, a wireless LAN system that uses orthogonal
frequency division multiplexing (e.g., 48 carriers carrying 64-QAM
signals in a 20 MHz wide channel) and defines the control layer to
utilize the media access control (MAC) protocol. A plurality of the
carriers are used as pilot tones to achieve receiver
synchronization. Multipath interference is controlled by having
many carriers propagating a low data rate signal, e.g., 256 kbit.
As such, the data rate for the system is limited within a given
bandwidth. Conversely, higher data rates necessitate greater
bandwidth. The greater the bandwidth demand, the fewer the number
of individual frequencies available to individually serve consumers
residing in multiple dwelling unit housing configurations.
[0005] Therefore, a need exists in the art for a broadband,
wireless network that provides a user with a flexible environment
for using and locating their communications appliances.
SUMMARY OF THE INVENTION
[0006] The present invention provides a neighborhood communications
gateway that accepts all incoming communications signals and
securely broadcasts those signals to residences throughout a
neighborhood. Each communications appliance within the neighborhood
is outfitted with a receiver that decodes the broadcast signals and
couples the signals to the input terminals of the associated
communications appliance. The system is completely "plug-and-play"
such that a user can quickly and easily utilize the gateway for
many communications appliances.
[0007] Each receiver is equipped with an antenna array and a
multipath signal processor to ensure that each communications
appliance received a robust, error free signal no matter where it
is located in the home. The multipath signal processor comprises
adaptive signal processing in both spatial and temporal domains to
ensure that multipath signals are sufficiently suppressed to enable
accurate decoding of the received signal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The teachings of the present invention can be readily
understood by considering the following detailed description in
conjunction with the accompanying drawings, in which:
[0009] FIG. 1 depicts a block diagram of a wireless network system
in accordance with the present invention;
[0010] FIG. 2 depicts a block diagram of a network gateway of FIG.
1;
[0011] FIG. 3 depicts a block diagram of a receiver of FIG. 1;
[0012] FIG. 4 depicts the frequency allocation for the wireless
network system of FIG. 1;
[0013] FIG. 5 depicts a block diagram of one embodiment of a back
channel transmitter;
[0014] FIG. 6 depicts a block diagram of a specific embodiment of a
receiver; and
[0015] FIG. 7 depicts a block diagram of a wireless network for
distributing information throughout a neighborhood of
receivers.
[0016] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures.
DETAILED DESCRIPTION
[0017] FIG. 1 depicts a block diagram of a broadband, wireless
communication system 100 in accordance with the present invention.
This system provides a broadband residential or small home office
(SOHO) wireless network. The system 100 comprises a gateway 104 and
a plurality of receiver nodes 120.sub.n (n is an integer). Each
receiver node 120.sub.n comprises a receiver 116.sub.n and a
communications appliances 110, 112, 114, and 118 coupled to the
receiver 116.sub.n. The gateway 104 receives a plurality of input
signals from a plurality of sources 102 including a cable feed, a
plain old telephone system (POTS) feed, a satellite television
feed, over-the-air television antenna, and the like. The gateway
104 is also optionally coupled to a residential controller 108 that
provides the ability to control various environmental aspects of a
residence (e.g., lighting, heating, cooling and so on) through a
wireless system.
[0018] As illustrated, FIG. 1 emphasizes that the entertainment
DTH, cable, and terrestrial channel tuners are located within the
gateway. Channel tuners are no longer associated with the
entertainment appliance. Air and physical interface access control,
payload mapper and demapper functions are executed within the logic
blocks of the gateway. Network control functions also are executed
within the logic of the gateway.
[0019] Conditional access control for DTH is handled within the
traditional decoder module of the A/V appliance so that encrypted
entertainment remains encrypted within the in-home network until
de-encrypted at the specific subscribing appliance. The traditional
interface between the logic block and the appliance can be, for
example, NRSS Level B for information flowing into the appliance
and I.sup.2C for control going back into the in-home network. Cable
pay per view (PPV) may be handled within the gateway.
[0020] The network itself, at 5.6 GHz, is comprised of three 100
MHz wide bands. These bands are channelized into fifty 6 MHz bands
where each channel carries 40 Mbits/secs for a total capacity of 2
Gbits/sec. Control and Internet links can be multiplexed within the
6 MHz wide in-home bands as shown, for example, in Table I:
1TABLE I Maximum Available Bands--Adjacent Channel Function Channel
Bandwidth Band Usage Delivery of encrypted 6 MHz 50* entertainment
from external broadband pipes to appliances at 40 Mbits/sec.
In-home multimedia/data 6 MHz 4 per channel** channels at 10
Mbits/sec Internet Uplinks at 1 6 MHz 10 per channel** Mbit/sec
*Dedicated non-multiplexed bands. **Multiplexed within one 6 MHz
band using a label protocol.
[0021] In a typical home configuration, assuming three DTH
picture-in-picture/internet TV sets and two PCs plus DTH and xDSL
Internet service subscriptions, the actual channel assignments for
this typical network are shown below in Table II:
2TABLE II Channel Function Bandwidth Required 6 MHz Bands Used
Delivery of encrypted 6 MHz 6 entertainment or internet to TVs (6 @
40 Mbits/sec) PC internet downlinks 6 MHz 1 (2 @ 10 Mbits/sec) PC
internet uplinks (2 @ 1 6 MHz 1 Mbits/sec)
[0022] Total 6 MHz band usage in this example is 8, leaving 42 free
for near neighbor usage and other 5.6 GHz services. Two 6 MHz bands
are dedicated to each TV to support regular high definition
television (HDTV) viewing via a DTH service provider plus windows
for HDTV PIP or Internet access, one 6 MHz band is dedicated to
downloading the Internet to the two or three PCs and another
lightly loaded channel is used for uploading from the PCs to the
Internet. A bandwidth utilization example is summarized in FIG.
4.
[0023] The modulated signals are transmitted from the gateway 104
to the receivers 116.sub.n through one or more antennas 106. The
transmitted signals are received and decoded at various locations
throughout the residence. The receivers 116 can be up to 100 meters
from the gateway 104. Each receiver 116 decodes the relevant
signals for the appliance that is attached to the receiver. For
example, the receiver 116.sub.1 decodes the signals that are
applicable to the personal computer 110, the receiver 116.sub.2
decodes the signals that are applicable to the television (or home
theatre system) 112, and so on. The uplink uses a time division
multiple access (TDMA) frame structure having timing synchronized
to downlink timing markers. Uplinks and downlinks are time based
synchronized in pairs. As such, the transmissions are packetized
and each packet is addressed to a particular receiver node.
Consequently, the gateway 104 can route signals to any receiver
node 120 within the system 100.
[0024] To facilitate the high data rates of the system, a 256/64
QAM modulation technology is used in the downlink. The occupied
bandwidth is less than 6 MHz allowing a sufficiently large number
of useable channels in the higher power portion of the 5 GHz band.
With appropriate IF filtering, adjacent channel performance levels
in excess of 40 dB can be achieved. A concatenated trellis code and
block code structure is used to provide adequate Forward Error
Correction or a Turbo Code method may also be employed based upon
the desired outcome of specific architectural refinements.
[0025] The QPSK modulation technology is used for the uplinks. This
occupies a bandwidth of less than 6 MHz with a maximum data rate of
10 Mbits/sec.
[0026] The most difficult class of problems associated with this
5.6 GHz band is that of multipath. In this frequency band and in a
home or SOHO environment, the multipath takes on a broad range of
characteristics including frequency flat fading, frequency
selective fading and high frequency Doppler distortion. To combat
this set of problems a multiple antenna diversity technique is used
in the form a spatial diversity equalizer/combiner. At least two
antenna inputs at a receiver node are equalized and combined to
reduce the effects of multipath encountered in the home or
home/office environments. This approach achieves the maximum level
of Quality of Service (QoS) that can be achieved without resorting
to complex MAC protocols and sophisticated reservation schemes.
[0027] To avoid interference and allow maximum user capacity, a
Carrier Sense Multiple Access Collision Detection, or CSMA/CD,
channel access technique is employed at system start-up. If
contention is sensed, the next best available channel may be
utilized by the system. Maximizing the overall available number of
channels within the allowable spectrum eases the burden in a
multidwelling unit application. A Forward Overhead Control Channel
is embedded in the downlink data stream, which advises and controls
uplink time slot allocation and channel bandwidth aggregation.
Channel access is also controlled through this mechanism.
[0028] The uplink consists of a TDMA based 10 MB/s QPSK modulated
data system in which burst demodulation must be employed to allow
multiple users to access the hub unit as required.
[0029] Finally, power control of both uplink and downlink traffic
channels, can be used to allow maximum utilization of spectrum in
high capacity environments and mitigate some of the technical radio
design challenges associated with wide dynamic signal range.
Because more than one user is multiplexed on a single carrier the
power control algorithm must accommodate the lowest recovered
signal strength user as its minimum case.
[0030] FIG. 2 depicts a detailed block diagram of the gateway 104
comprising a gateway logic 240 and a radio section 238. The radio
section 238 comprises a plurality of tuner modules 202 (e.g.,
direct broadcast satellite (DBS), ultra-high frequency (UHF), very
high frequency (VHF), and so on) and a transceiver 216. The gateway
logic 240 comprises a plurality of demodulators 204 (e.g.,
quadrature phase shift keying (QPSK), vestigial side band (VSB),
standard television and the like), decoders 206, a reconfigurable
ATM adaptation layer 2 242, a microprocessor 208, a gateway
firewall 210, an encoder 212, a modulator 214, a demodulator 218
and a decoder 220. The various sources of RF signals are coupled to
the tuner modules 202, which select particular signal channels for
reception. Each appliance has a corresponding tuner module 202. The
tuner modules filter and down convert each of the selected
channels. The channels are selected by a user or users via the back
channel communication link from the receivers 116 to the gateway
104. The back channel operation is discussed below. The
demodulators 204 demodulate the down converted signals. The
decoders 206, then decode the signals including performing error
correction to form baseband video. The baseband video is coupled to
the gateway interface 210. The tuner modules 202, the demodulators
204, and the decoders 206 are all controlled by the microprocessor
208.
[0031] The reconfigurable ATM adaptation layer 2 242 couples the
gateway firewall 210 to an xDSL CPE stream to enable the system to
be used to distribute voice, data, fax, multimedia content, and
TCP/IP Internet services throughout a residence. The content from
the xDSL stream can then be displayed by any one of the appliances
in the network.
[0032] The gateway firewall 210 digitizes the decoded signals (if
necessary) and provides firewall services. The firewall services
ensure that unauthorized users cannot access the gateway from
outside the residence without proper authority. Additionally, the
gateway firewall 210 provides encryption to ensure that neighboring
residences are not capable of viewing each other's programming. The
firewall and encryption services are provided by using a well-known
protocol such as the media access control (MAC) protocol.
[0033] The encrypted baseband video signals are coupled to an
encoder 212. The encoder 212 compresses the signal using, for
example, run-length coding, or some other form of lossless
encoding. The encoded signal is coupled to modulator 214, where the
signal is modulated onto a 5-6 GHz carrier. The modulation is an
M-ary quadrature amplitude modulation (QAM). To transmit broadband
signals such as HDTV, the modulation is selected to be 256-ary QAM.
For lower bandwidth signals, the modulation index can be lowered
to, for example, 64.
[0034] A transceiver 216 amplifies the modulated signal and couples
the signal to a pair of antennas 106. Specifically, the signal
passes through a wide-band amplifier 222, a bandpass filter 224, a
diplexer 228, and a power splitter/combiner 226. The diplexer 228
and band pass filter 224 may be fabricated as a single component.
The diplexer 228 and power splitter 226 enables the transmitter and
receiver to utilize the same antennas 106. The transmitter portion
of the transceiver 216, for example, transmits a 1 Watt signal in
the 5.75-5.85 GHz band (the UNII-band). Each of the transmitted
signals carries 20-40 Mbps in a channel bandwidth of approximately
6 MHz. As such, many 6 MHz channels (one or more for each
appliance) are transmitted in the UNII-band.
[0035] Additional antenna elements could be used with dynamic, beam
forming circuitry such that the transmitted signal is "pointed" at
the appliance that is to receive the signal being transmitted at
any instant in time. Such antenna control provides multipath signal
suppression at the receiver plus further enhancements of QoS
without the complications of more complex MAC protocols.
[0036] The antennas 106 also receive control signals from various
appliances within the residence. In one embodiment of the invention
(not shown), only a single antenna is coupled to the back channel
receiver 201 in the gateway 104. In another embodiment, both
antennas are coupled to the receiver 201 via a splitter/combiner
226 and diplexer 228. Combining the antenna signals forms a spatial
diversity combiner that suppresses multipath interference. An
adaptive spatial diversity combiner that can be used in the gateway
transceiver is described with reference to FIG. 2. Because the back
channel data rate is relatively low, the back channel modulation is
generally BPSK, QPSK or 4-ary QAM, both of which are relatively
easy to receive, even in a noisy environment. As such, diverse
antennas are not generally necessary.
[0037] The received signals, known as back-channel signals, are
coupled through a diplexer 228, band pass filter 230, amplifier
232, mixer 236 and into a demodulator 218. The transceiver 216
provides amplification and downconversion such that the output of
the transceiver 216 is an IF signal with a relatively high
signal-to-noise ratio (SNR). The back-channel signal is typically
in the 5.125-5.225 GHz band (the UNII-band) and transmitted from
the network appliances using 50 mW. The back channel can support 10
Mbits/sec using burst mode QPSK modulation. The demodulator 218
extracts the modulation (a baseband signal) from the carrier signal
and couples the baseband signal to the decoder 220. The decoder 220
decodes the baseband signal. The back channel signal carries
commands from the network appliances (120 of FIG. 1) to instruct
the gateway 104 as to what signals to transmit to the appliances.
The decoded signals are coupled to the microprocessor 208 for
implementation.
[0038] FIG. 3 depicts a block diagram of a receiver 116 of FIG. 1
that uses a multipath processor 301 (referred to as a spatial
diversity combiner) to combat multipath interference. Each antenna
106A and 106B is respectively coupled to tuners 304 and 306. These
tuners 304 and 306 select one of the 64 available channels. The
tuners 304 and 306 filter and downconvert the received signal to
near baseband. The near baseband signals are respectively coupled
to the analog-to-digital (A/D) converters 304 and 306. The
digitized signals are applied to the timing recovery circuitry 308.
The timing recovery circuitry 308 ensures that the A/D converters
304 and 306 accurately sample the symbols in the near baseband
signal.
[0039] The samples are then coupled to separate spatial equalizers
310 and 312. These equalizers are multi-tap feed forward equalizers
(FFE) that delay their respective signals to achieve equal delays
in the received signals. The most difficult class of problems
associated with this 5.6 GHz band is that of multipath. In this
frequency band and in a home or SOHO environment, the multipath
takes on a broad range of characteristics including frequency flat
fading, frequency selective fading and Doppler distortion. To
combat this set of problems a multiple antenna diversity technique
is used to form a spatial diversity equalizer/combiner. At least
two antenna inputs are equalized and combined to reduce the effects
of multipath encountered in the home or home/office environments.
Once spatially equalized by equalizers 310 and 312, the two signals
are combined in combiner 314. The output of the combiner 314 is
coupled to a single circuit 316 comprising both a temporal
equalizer and carrier loop recovery circuit. The equalizer/carrier
recovery circuit 316 comprises a decision feedback equalizer (DFE)
that removes intersymbol interference and a carrier recovery loop
that extracts the carrier from the equalized symbols.
[0040] The carrier is used to derotate the symbols for sampling
using the symbol sampler 318. Within the subtractor 320, the symbol
sample is compared to the unsampled symbol to produce a symbol
error that is coupled to the tap control 322. The tap control 322
uses the error signal to produce tap weight adjustments for the
three equalizers: the two spatial equalizers 310 and 312 and the
temporal equalizer 316. To provide such multipath processing in the
gateway, similar circuitry may be included in the transceiver of
the gateway.
[0041] The sampled symbols are coupled to the appliance specific
processor 324. The processor 324 performs the necessary processing
to convert the symbol stream into a signal that can be used by the
appliance. For example, if the appliance is an NTSC television, the
appliance specific processor 324 would convert the symbol stream
into an NTSC signal. Receivers designed for other appliances
convert the symbols into signals that are appropriate for those
appliances. For example, an NTSC signal would be digitized and 3-D
comb filtered in the gateway prior to encoding and transmission to
a node in the system. An NTSC signal may be digitized into a
standard definition (SD) digital signal. The receiver would convert
the digital signal into a signal that is compatible with the
television receiver. As such, the system can accommodate legacy
television systems.
[0042] FIG. 5 depicts a back channel transmitter 500 for television
appliance. The television set decoder 502 couples to the I.sup.2C
bus 510 of the back channel transmitter 500. The I.sup.2C bus 510
carries command and control signals to a logic block 504. The logic
block 504 contains a modulator/FEC encoder, payload mapper, MAC,
transmit band selection and transmit control logic. The logic block
504 is coupled to the upconverter/modulator/frequency synthesizer
block 506. The logic block 504 sends a control signal and an 8 bit
data signal to the block 506. Block 506 modulates the command
signal onto a carrier and upconverts the modulated signal to the
back channel band. The signal is then coupled to one or more
antennas 508. This transmitter 500 receives, for example, channel
turning commands from the television 502 and sends those commands
to the gateway. The gateway then adjusts a tuner module to receive
the specified channel. Content from that channel is then wirelessly
sent to the television appliance for display.
[0043] FIG. 6 is a block diagram of an illustrative receiver 600
that is used to receive both a primary television signal and a
picture-in-picture (PIP) signal from the wireless network. The PIP
signal may be an HDTV signal. Also the PIP signal may be received
by a separate device such as a hand-held wireless device. The
receiver 600 comprises one or more antennas 602A and 602B, a pair
of down converters 604A and 604B, a pair of low noise amplifiers
(LNAs) 606A and 606B, a pair of tuners 608A and 608B, and a logic
block 610. The logic block 610 is coupled to a television set
decoder 612.
[0044] The antennas 602A and 602B receive signals from the wireless
network. Although two antennas are shown, those skilled in the art
should understand that each antenna 602A and 602B may be an array
of antennas and a diversity combiner. The signals are coupled to
the down converters 604A and 604B to select a particular channel in
the 5.725-5.8256 Hz band. The selected channels (one for each down
converter) are converted to a 725-825 MHz band.
[0045] The down converters 604A and 604B are each coupled to an LNA
606A and 606B that adjust the amplitude of the signal. The gain of
each LNA 606A and 606B is controlled by a gain control signal from
the logic block 610. The amplified signals are each coupled to the
tuners 608A and 608B. These tuners may be integrated circuit tuners
similar to that disclosed in U.S. patent application Ser. No.
09/457,258, filed Dec. 8, 1999 and incorporated herein by
reference. The tuners 608A and 608B are controlled by signals
generated by the logic block 610.
[0046] The logic block 610 receives 10 bit digital signals from the
tuners 608A and 608B. The logic block 610 provides diversity
combining (if the down converters and tuners select the same
channel), demodulation, forward error correction, payload
demapping, MAC functionality, band tuner control, de-encryption,
and the like. The logic block 610 produces 8-bit signals in NRSS-B
format that are coupled to the television set decoder 612. The
decoder 612 couples control signals to the logic block 610.
[0047] The receiver 600 may select two different television
programs from the wireless network such that one signal can be
displayed on the television as a primary video signal and the
second signal can be displayed on the PIP television.
Alternatively, one of the signals may be an Internet channel so
that for example, the PIP could display an Internet web site or
sites or other information provided by the Internet.
[0048] FIG. 7 depicts a block diagram of a wireless communications
system 700 that is used to distribute information throughout a
neighborhood of users, i.e., a wide area network. The system 700
provides broadband communications to the residences of a
neighborhood, i.e., transmission over "the last mile".
[0049] The system 700 comprises a neighborhood gateway 702 and a
plurality of receivers 704. The receivers 704 are coupled to
associated network appliances 706. The gateway 702 received all or
most of the communication signals used by a neighborhood of users.
Such signals include telephone signals (POTS), analog and digital
cable television signals, computer data signals (sDSL, cable modem,
and the like), satellite television signals, over-the-air
television and radio broadcasts and the like.
[0050] This gateway 702 operates in much the same manner as the
gateway 104 of FIGS. 1 and 2 in that the input signals are
rebroadcast to user receivers 704 upon request from the receivers
704. The gateway 702 selects the information requested by each
receiver 704 and transmits the information to the requesting
receiver. The receivers 704 each contain a back channel transmitter
712 that is used for transmitting the requests from the receivers
704 to the gateway 702 via a back channel communications link. The
forward and back channel links are represented by double-headed
arrows 708. Each receiver 704, as in the residential application,
is individually addressable such that the information is
transmitted and received in a secure manner. A residence within the
neighborhood may contain a multitude of receivers 704 such that all
the communications needs of a given residence are serviced by the
neighborhood gateway.
[0051] As with the residential network, the neighborhood network is
subject to multipath fading and distortion. Such multipath signal
degradation is mitigated by the use of the diversity antenna
technique described above with respect to FIGS. 1-3. As such, each
receiver 704 comprises a pair of receiving antennas 710.
[0052] Although various embodiments that incorporate the teachings
of the present invention have been shown and described in detail
herein, those skilled in the art can readily devise many other
varied embodiments that still incorporate these teachings.
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