Single-LNB satellite data receiver

Details Single-LNB satellite data receiver Single-LNB satellite data receiver

1999-08-30

2002-08-06

Pham, Chi (Department: 2631)

Pulse or digital communications

Receivers

C725S068000, C725S069000, C725S071000, C725S085000, C725S110000, C725S131000, C455S003020

Reexamination Certificate

active

06430233

ABSTRACT:

BACKGROUND OF THE INVENTION
1.1 Field of the Invention
The present invention relates generally to the transmission of data services over a geosynchronous satellite communications network, and more, in particularly, relates to the transmission of services to satellite communications networks having Direct-To-Home (DTH) satellite receivers including a single-LNB (Low-Noise Block) in the outdoor unit (ODU) antenna assembly.
1.2 Description of Related Art
1.2.1 Direct-To-Home Satellite Television Reception
As is well known in the art, the signals broadcast from a geosynchronous, DTH satellite are sent on one of two polarizations, which allows two sets of signals to be carried by one frequency band. In order to receive an analog TV program or digital carrier, a receiver must select the proper polarization (rejecting all signals on the other polarization) and tune to the appropriate frequency.
FIG. 1
illustrates the receive portion 10 of a typical satellite DTH satellite system.
A home is typically equipped with:
An ODU
11
including:
An antenna mount
12
, which holds the remainder of the ODU
11
in a fixed position so that signals can be received from a single, geosynchronous orbital position.
A parabolic reflector
14
, which gathers received signals from a single geosynchronous orbital position and passes the concentrated signals to a feed horn (FH)
16
.
FH
16
takes the concentrated signals from the parabolic reflector
14
and passes them to a single-LNB
18
.
The Single-LNB
18
:
selects one of the two sets of polarized signals from the geosynchronous orbital position at the direction of a set-top box
13
.
low-noise amplifies the complete frequency band,
translates the amplified signals to L-Band (e.g. 950 Mhz to 2150 MHz) and
passes the resulting signals via a coaxial cable
17
to the set-top box
13
.
The Coaxial Cable
17
carries the L-band satellite receive signals to the set-top box
13
. The coaxial cable
17
carries power and polarization selection from the set-top box
13
to the single-LNB
18
.
The Set-Top Box
13
allows the end-user of TV
14
to select a single TV channel from those receivable by the ODU
11
. The set-top box
13
converts the TV channel from its satellite broadcast form to the form accepted by an unmodified broadcast television (e.g. NTSC or PAL) and passes the signal to the TV
14
.
The set-top box
13
passes the polarization selection to the single-LNB
18
through the coaxial cable
17
in different ways, depending on the type of single-LNB
18
. Some single-LNBs receive the desired polarization by detecting the presence or absence of a 22 kHz tone on the coaxial cable
17
. Other single-LNBs receive the desired polarization by measuring the dc voltage received on the coaxial cable
17
. Still other single-LNBs receive the desired polarization in other ways, but always from signals on the coaxial cable
17
.
FIG. 1
describes a vast majority of the over 40 million Direct-To-Home receivers currently in use. A major cost factor with the system in
FIG. 1
is that the installation of the ODU
11
and coaxial cable
17
is typically beyond what a normal consumer would consider doing on their own and is typically done at significant expense by a professional installer.
1.2.2 Digital Satellite Direct-To-Home Systems
As is well known to those skilled in the art, typical DTH systems are designed so that multiple digital services (e.g. television, audio and other services) are multiplexed into a single multimegabit per second digital carrier. The multiplexing is performed by means of fixed-length packets such as the 188-byte packets defined by what is known as the MPEG-2 transport system and as defined in the International Standards Organization (ISO) standard ISO 13818 Part 1, the contents of which are hereby incorporated by reference. Forward error-correcting codes are utilized at the bit level so that, under normal weather conditions, data is virtually never lost.
Each 188-byte MPEG-2 transport packet contains an address field, referred to as a program identifier (PID), which uniquely identifies the service carried by the packet. Digital DTH systems deliver a service's packets in order even though the multiplexing and remultiplexing of services may result in the resequencing of packets from different services.
Digital Video Broadcast (DVB), a European standards body, has defined standards for carrying data services over MPEG-2 transport systems. Three of these standards are:
Data Piping—where an individual packet ID (PID) carries a byte stream within the 184 byte payload field of the 188-byte MPEG packets.
Data Carousel—the DVB standard multicast file transfer mechanism where given files are repeatedly transmitted so that if the receiver is unavailable when a file is first transmitted or the first reception is errored, the receiver can come back and receive a substantial transmission.
Multiprotocol Encapsulation—where collections of internet protocol (IP) packets, typically IP multicast packets, are carried within the payload fields of MPEG packets in a standard way.
1.2.3 Digital Satellite Direct-To-Home Data Services
Various kinds of data services can be delivered to end-users via digital satellite DTH systems. These services can typically be categorized as follows:
Multicast file transfer—the delivery of complete files of digital data containing software, Internet Web pages, digital music, etc. For most multicast file transfers, the data is not extremely real-time. That is, the transmitter has some flexibility regarding when the multicast file transmission takes place. A partial or errored reception of a multicast file transfer is of no use to the receiver.
Carousel—this is a variation on the multicast file transfer where given files are repeatedly transmitted so that if the receiver is unavailable when a file is first transmitted, or the first reception is errored, the receiver can come back and receive a subsequent transmission.
Streaming multicast media—examples of this category include streaming digital audio and video. Streaming multicast media contains a characteristic whereby a user typically joins a stream in the middle of its transmission, and the transmission is useful even when not received completely from beginning to end and even in the presence of occasional errors.
Unicast alert—examples of this include sending of “pages” or e-mail arrival notifications. This category is exemplified by the transmission of a small number of packets to a single end-user where the data transmitted must be received by the intended user with high-probability. Often unicast alerts are made robust against transmission errors by means of repeat transmission.
These kinds of data services can be carried either natively via data piping or data carousels or some other similar mechanism or can be carried via IP packets and multiprotocol encapsulation.
1.2.4 Digital Satellite Reception
FIG. 2
illustrates the digital reception part
20
of a typical digital satellite receiver
23
.
The digital reception part
20
includes an ODU
11
, a coaxial cable
17
, and a digital satellite receiver
23
. The ODU
11
further includes an antenna mount
12
, a parabolic reflector
14
, an FH
16
, and an LNB
218
. The digital satellite receiver
23
further includes a tuner
232
, a demodulator/forward error correcting (FEC) decoder
234
, and a controller
236
.
As discussed above with respect to
FIG. 1
, the LNB
218
translates the signals from the satellite to L-band. As is well known to those skilled in the art, a particular LNB somewhat inaccurately performs this translation. The combination of unit-to-unit and temperature variation typically allows the translation to be inaccurate by approximately ±4 MHz.
The term “acquire”, in the context of satellite digital receivers, refers to the process of obtaining successful reception of a digital carrier. When a signal is “acquired”, it is being received. If acquisition is lost, then the signal is no longer being received and must be re-acquired.
In order to acquire a typical satellite digital carri

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