US8730798B2

US8730798B2 - Transmitter channel throughput in an information network

Info

Publication number: US8730798B2
Application number: US12/774,326
Authority: US
Inventors: Avi Kliger; Philippe Klein; Yitshak Ohana
Original assignee: Broadcom Corp
Current assignee: Avago Technologies International Sales Pte Ltd
Priority date: 2009-05-05
Filing date: 2010-05-05
Publication date: 2014-05-20
Also published as: US20100284474A1

Abstract

Apparatus and methods for transmitting information over a home coax network. The apparatus and methods may involve a physical layer frequency domain signal preprocessor and a physical layer time domain signal transmitter. The transmitter may be configured to receive the signal from the preprocessor and transmit the signal over coax that is in radiofrequency communication with a plurality of network nodes, the transmitter having a first transmission channel and a second transmission channel. The signal may be received by a receiver on the network. The receiver may have a MAC-to-PHY interface that is configured to receive signals from single-transmission-channel transmitters.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Application No. 61/175,496, filed on May 5, 2009, which is hereby incorporated by reference herein in its entirety.

FIELD OF TECHNOLOGY

The present invention relates generally to information networks and specifically to transmitting information such as media information over communication lines such as coaxial cable (hereinafter “coax”), thereby to form a communications network.

BACKGROUND

Home networking over coax is a known technology which has vast commercial potential.

Home network technologies having a packet aggregation functionality are known generally. The Multimedia over Coax Alliance (MoCA™), at its website mocalliance.org, provides an example of a suitable specification (MoCA 1.0) for networking of digital video and entertainment through existing coaxial cable in the home which has been distributed to an open membership. Packet aggregation functionality is not provided. MoCA 1.0 specification is incorporated by reference herein in its entirety.

Home networking over coax taps into the vast amount of unused bandwidth available on in-home coax. More than 70% of homes in the United States have coax already installed in the home infrastructure. Many have existing coax in one or more primary entertainment consumption locations such as family rooms, media rooms and master bedrooms—ideal for deploying networks. Home networking technology allows homeowners to utilize this infrastructure as a networking system and to deliver other entertainment and information programming with high QoS (Quality of Service).

The technology underlying home networking over coax provides high speed, high QoS, and the innate security of a shielded, wired connection combined with state of the art packet-level encryption. Coax is designed for carrying high bandwidth video. Today, it is regularly used to securely deliver millions of dollars of pay per view and premium video content on a daily basis. Home networking over coax can also be used as a backbone for multiple wireless access points used to extend the reach of wireless network throughout a consumer's entire home.

Home networking over coax provides a consistent, high throughput, high quality connection through the existing coaxial cables to the places where the video devices currently reside in the home without affecting the existing analog or digital services present on the cable. Home networking over coax provides a primary link for digital entertainment, and may also act in concert with other wired and wireless networks to extend the entertainment experience throughout the home.

Currently, home networking over coax works with access technologies such as ADSL and VDSL services or Fiber to the Home (FTTH), that typically enter the home on a twisted pair or on an optical fiber, operating in a frequency band from a few hundred kilohertz to 8.5 MHz for ADSL and 12 MHz for VDSL. As services reach the home via xDSL or FTTH, they may be routed via home networking over coax technology and the in-home coax to the video devices. Cable functionalities, such as video, voice and Internet access, may be provided to homes, via coaxial cable, by cable operators, and use coaxial cables running within the homes to reach individual cable service consuming devices locating in various rooms within the home. Typically, home networking over coax type functionalities run in parallel with the cable functionalities, on different frequencies.

The coax infrastructure inside the house typically includes coaxial wires and splitters. Splitters used in homes typically have one input and two or more outputs and are designed to transfer signals from input to outputs in the forward direction, or from outputs to input in the backward direction and to isolate splitter outputs and prevent signals from flowing room/outlet to room/outlet. Isolation is useful in order to a) reduce interference from other devices and b) maximize power transfer from Point Of Entry (POE) to outlets for best TV reception.

The MoCA technology is specifically designed to go backwards through splitters (insertion) and go from splitter output to output (isolation). All outlets in a house can be reached from each other by a single “isolation jump” and a number of “insertion jumps”. Typically isolation jumps have an attenuation of 5 to 40 dB and each insertion jump attenuates approximately 3 dB. MoCA has a dynamic range in excess of 55 dB while supporting 200 Mbps throughput. Therefore MoCA can work effectively through a significant number of splitters.

MoCA is a managed network that is unlike some other home networking technologies. It is specifically designed to support streaming video without packet loss, thus providing very high video quality between outlets.

Digital cable programming is delivered with threshold Packet Error Rate (PER) of below 1e-6. The home network should preferably have similar or better performance so as not to degrade viewing.

Later versions of the MoCA specification may require or permit that a MoCA device transmit and receive on more than one channel.

The disclosures of any publications and patent documents mentioned in the specification, and of the publications and patent documents cited therein directly or indirectly, are hereby incorporated by reference.

SUMMARY OF THE INVENTION

A system and/or method for transmitting information over a home communications network, substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:

FIG. 1 shows a schematic diagram of an illustrative single or multi-chip device that may be used in accordance with principles of the invention;

FIG. 2 shows, in part, apparatus that may be used in accordance with the principles of the invention;

FIG. 3 shows apparatus in accordance with the principles of the invention.

FIG. 4 shows other apparatus in accordance with the principles of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Apparatus and methods for transmitting information over a home coax network are provided. The apparatus and methods may involve a physical layer frequency domain signal preprocessor; and a physical layer time domain signal transmitter. The transmitter may be configured to receive the signal from the preprocessor and transmit the signal over coax that is in radiofrequency communication with a plurality of network nodes, the transmitter having a first transmission channel and a second transmission channel.

The frequency domain preprocessor may receive a signal that may be a bit stream. The preprocessor may include one or more of an encryption module, which may be based on the advanced encryption standard, a forward error correction module, a low density parity check encoder, a symbol padding module, an adaptive constellation multitone padding module, a byte scrambler and a frequency domain preamble generator.

The preprocessor may transmit the signal to the transmitter. The transmitter may be in communication with a network. The network may include a coax backbone. The network may be a MoCA 1 network. The network may be a MoCA 2 network. the network may include one or more nodes that conform to the MoCA 1 specification and one or more nodes that conform to the MoCA 2 specification.

In some embodiments, the first transmission channel may be configured to transmit a first portion of the signal to the coax; and the second transmission channel may be configured to transmit a second portion of the signal to the coax.

The apparatus may include a semiconductor chip. The first and second channels may be integral to the chip. In some embodiments, the first channel may be substantially parallel to the second channel.

In MoCA-based networks, there may be one or more defined communication bands. In some embodiments, the first channel and the second channel may communicate in the same band.

The first channel may transmit the first portion of the signal at the same time as the second channel transmits the second portion of the signal. In some embodiments, transmission of the first portion and the second portion may be simultaneous. In some embodiments, concurrent transmission on the first and second channels may provide transmitter throughput that is greater than the throughput of a single channel transmitter.

Some embodiments may include an oscillator. The oscillator may provide a timing signal to the first and second transmitter channels. The first and second transmitter channels may transmit the signal based on the timing signal.

In some embodiments, each of the first and second portions of the signal may include a preamble. The first portion may include a first preamble. The second portion may include a second preamble. The first channel may be configured to transmit the first preamble in response to a trigger in the timing signal. The second channel may be configured to transmit the second preamble in response to the same trigger.

In some embodiments, the first and second channels may transmit their respective signal portions on different carrier frequencies. The first channel may be configured to transmit the first portion at a first frequency. The second channel may be configured to transmit the second portion at a second frequency. The first and second frequencies may be different.

Some embodiments may include a subcarrier mapper. The subcarrier mapper may be configured to define the first portion and the second portion based on bit loading. For example, the subcarrier mapper may direct portions of the signal to the transmission channels in a manner that distributes bit loading between the channels.

In some coax-based home networks, such as some MoCA networks, each physical (“PHY”) RF transmission channel may be configured to transmit using 512 subcarriers over a 100 MHz transmission spectrum. The signal-to-noise ratio (“SNR”) of a sub-carrier depends in part on the sub-carrier frequency. Higher SNR ratios may permit higher bit loading. The subcarrier mapper may be configured to execute an algorithm that allocates bits to the different sub-carriers based on the SNR of each sub-carrier.

Each of the first and second transmission channels may be configured to transmit using 512 sub-carriers. When both first and second transmission channels are present in a transmitter, 2×512=1,024 subcarriers may be available for transmission. When n transmission channels are present in a transmitter, n×512=512n, n=1, 2, 3, . . . , N, subcarriers may be available for transmission. Total number of subcarriers, N, may be any suitable number. Under some home networking specifications, such as MoCA 1 and MoCA 2, and any other suitable specifications, MAC level logic and protocols may be the same for different values of N. For example, a MAC transmission protocol that is configured for transmission when N=1 may also be executed when N=2 or N=3.

Each of the first and second transmission channels may include one or more of a BIN scrambler, an ACMT modulator, an OFDM modulator, a DAC and anti-aliasing filter, and an RF converter.

Some embodiments may include an output buffer that is in communication with the time domain signal preprocessor. The buffer may be configured to store output from the preprocessor. For example, the buffer may store first output from the preprocessor. The first output may be the first signal portion.

Some embodiments may include control logic that transfers the first output from the buffer to the first transmission channel. The transfer may occur at substantially the same time as the preprocessor transfers second output, corresponding to the second portion, to the second transmission channel.

Methods in accordance with the principles of the invention may include a method for transmitting information over a home network. The method may include culling from a digital home network information signal first information packets and second information packets; transmitting the first information packets over coax that is in radiofrequency communication with a plurality of network nodes; and transmitting the second information packets. The information packets may be transmitted in such a manner that, when a MAC interface is in communication with the home network, the first information packets and the second information packets are configured to transit the MAC interface. The MAC interface may be a MoCA MAC interface.

In some embodiments, when the first and second information packets are present on a carrier frequency in a coax conductor, they correspond operationally to a portion of a MoCA 2 1024-sub-carrier signal.

In some embodiments, the method may include preprocessing and then buffering the first information packets. The method may include performing frequency domain preprocessing on the second information packets while the first information packets are buffered.

Illustrative embodiments of apparatus and methods in accordance with the principles of the invention will now be described with reference to the accompanying drawings, which form a part hereof. It is to be understood that other embodiments may be utilized and structural, functional and procedural modifications may be made without departing from the scope and spirit of the present invention.

As will be appreciated by one of skill in the art, the invention described herein may be embodied in whole or in part as a method, a data processing system, or a computer program product. Accordingly, the invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software, hardware and any other suitable approach or apparatus.

Furthermore, such aspects may take the form of a computer program product stored by one or more computer-readable storage media having computer-readable program code, or instructions, embodied in or on the storage media. Any suitable computer readable storage media may be utilized, including hard disks, CD-ROMs, optical storage devices, magnetic storage devices, and/or any combination thereof. In addition, various signals representing data or events as described herein may be transferred between a source and a destination in the form of electromagnetic waves traveling through signal-conducting media such as metal wires, optical fibers, and/or wireless transmission media (e.g., air and/or space).

FIG. 1 shows a single or multi-chip module 102 according to the invention, which can be one or more integrated circuits, in an illustrative data processing system 100 according to the invention. Data processing system 100 may include one or more of the following components: I/O circuitry 104, peripheral devices 106, processor 108 and memory 110. These components may be coupled together by a system bus or other interconnections 112 and are disposed on a circuit board 120 in the data processing system 100 that may be in communication with a coax medium 125 via an interface.

For the sake of clarity, the foregoing description, including specific examples of parameter values provided, is sometimes specific to certain protocols such as those identified with the name MOCA™ and/or Ethernet protocols. However, this is not intended to be limiting and the invention may be suitably generalized to other protocols and/or other packet protocols. The use of terms that may be specific to a particular protocol such as that identified by the name MOCA™ or Ethernet to describe a particular feature or embodiment is not intended to limit the scope of that feature or embodiment to that protocol specifically; insteadm the terms are used generally and are each intended to include parallel and similar terms defined under other protocols.

It is appreciated that software components of the present invention including programs and data may, if desired, be implemented in ROM (read-only-memory) form including CD-ROMs, EPROMs and EEPROMs, or may be stored in any other suitable computer-readable medium such as but not limited to disks of various kinds, cards of various kinds and RAMs. Components described herein as software may, alternatively, be implemented wholly or partly in hardware, if desired, using conventional techniques.

Features of the present invention which are described in the context of separate embodiments may be provided in combination in a single embodiment. Conversely, features of the invention which are described for brevity in the context of a single embodiment may be provided separately or in any suitable subcombination.

As will be appreciated by one of skill in the art, the invention described herein may be embodied in whole or in part as a method, a data processing system, chip, component or device, or a computer program product. Accordingly, the invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software, hardware and any other suitable approach or apparatus.

The invention may be operational with numerous other general purpose or special purpose computing system environments or configurations. Examples of well known computing systems, environments, and/or configurations that may be suitable for use with the invention include, but are not limited to, personal computers, server computers, hand-held or laptop devices, mobile phones and/or other personal digital assistants (“PDAs”), multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like. In a distributed computing environment, devices that perform the same or similar function may be viewed as being part of a “module” even if the devices are separate (whether local or remote) from each other.

The invention may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules may include routines, programs, objects, components, data structures, etc., that perform particular tasks or store or process data structures, objects and other data types. The invention may also be practiced in distributed computing environments where tasks are performed by separate (local or remote) processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.

FIG. 2 shows illustrative transmitter 200. Transmitter 200 may include preprocessor 201. Frequency domain signal S, which may be a bit stream, may be fed to encryption module 204, which may be an advanced encryption standard (“AES”) based module. Module 204 may also provide padding. Signal S may then be passed to forward error correction (“FEC”) module 206. Module 206 may provide padding to 2080 or 4160 bits. Signal S may then be passed to low density parity check encoder 208. From encoder 208, signal S may be passed to symbol padding module 210. Module 210 may provide orthogonal frequency domain multiplexing (“OFDM”) padding. Signal S may then be passed to byte scrambler 212.

Frequency domain preamble generators 214 may provide frequency domain preambles.

Signal S is then passed to subcarrier mapper 216.

Signal S is then passed to bin scrambler 218 in single transmitter channel 220. Transmitter channel 220 converts signal S into an RF time domain signal.

Transmitter channel

220 may include OFDM modulator 222, filter 224 and RF converter 226. Time domain preamble generators 228 may provide time domain preambles to the signal.

Single channel transmitters may require reduced chip set cost in comparison to that of bonded channel transmitters. When 800 Mbps is not required for transmission, a single channel transmitter may have less overhead than bonded channel transmitters. Single channel transmitters may not require management of between-channel interference or filtering and may not require a guard band.

Transmitters such as 200 may transmit in OFDM transmission mode at 800 Mbps using a single channel transmitter. Illustrative characteristics of the transmission mode, using MoCA 2 as an example, are shown in Table 1.

TABLE 1

Illustrative single transmission channel features.

	Illustrative Feature	Value

	Sampling rate
	200 MHz (nominal)
	Sub-carriers	1024
	Maximal CP size	256 or greater
	available sub-carriers	944 or more
	maximum constellation size	10 bpcs (QAM1024) or more
	maximum PHY Rate	>1480 Mbps (on a flat channel,
		CP = 100, 10 bpsc) or more
	PHY Rate	>1000 Mbps (on a flat channel,
		CP = 100, 7 bpsc) or more

FIG. 3 shows illustrative transmitter 300. Transmitter 300 may include preprocessor 301. Transmitter 300 may include bonded

transmission channels

320 and 321. Bonded channels may provide good channel selection. Bonded channels may be physically adjacent each other. Bonded channels may be physically parallel to each other. Each channel of the bonded channels may provide performance that may have one or more of the features identified in Table 1.

Elements 304-316 and 328 of transmitter 300 may be substantially similar, if not identical, to corresponding elements 204-216 and 228 of transmitter 200 (shown in FIG. 2).

Channels

320 and 321 may both correspond to channel 220 (shown in FIG. 2). The total throughput of

channels

320 and 321 may be about twice that of channel 220.

Channels

320 and 321 may be on the same MoCA band. Each may be compliant with the same baseline PHY layer device. The two channels may transmit simultaneously and may be synchronized. In some embodiments, the two channels may have the same sampling clock and/or the same LO frequency source oscillator. The first bit of preamble for each of the channels may be transmitted on the same sampling clock.

In some embodiments, the two channels may be consecutive in frequency. When the two channels are consecutive in frequency, interference and large differences in attenuations may be reduced.

A MAC interface in communication with transmitter 300 may “see” a single 1024-sub-carrier PHY corresponding to the two different physical channels. Data may be distributed between the two channels according to the bit loading.

The two channels may support a single Probe 1 transmission and report.

Bit loading may be calculated simultaneously on the two channels.

FIG. 4 shows illustrative transmitter 400. Elements 401-421 of transmitter 400 may correspond to, and may have some or all of the features of, elements 301-321 of transmitter 300 (shown in FIG. 3). Transmitter 400 may include preprocessor output buffer 402. Preprocessor output buffer 402 may store first information packets that are processed by preprocessor 401. While preprocessor output buffer 402 buffers the first information packets, preprocessor 401 may preprocess second information packets. When the second information packets are preprocessed, the first information packets and the second information packets may be, at substantially the same time, transmitted to transmission subcarrier mapper 316 and

transmission channels

320 and 321.

Preprocessor output buffer 402 is shown as being upstream from frequency domain preamble generators 314. In some embodiments, preprocessor output buffer 402 may be downstream from frequency domain preamble generators 314. In such embodiments, a preamble for the first information packets may be stored in the preprocessor output buffer.

Thus, systems and methods for transmitting information over a home network have been provided. Persons skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments, which are presented for purposes of illustration rather than of limitation.

Claims

What is claimed is:

1. Apparatus for transmitting information over a coax network, the apparatus comprising:

a physical layer frequency domain signal preprocessor; and

a physical layer time domain signal transmitter that is configured to receive a signal from the preprocessor and transmit the signal over a coax medium that is in radio frequency communication with a plurality of network nodes, the transmitter having a first transmission channel configured to transmit a first portion of the signal during an identified time period and a second transmission channel configured to transmit a second portion of the signal during the identified time period.

2. The apparatus of claim 1 wherein, when the signal is a MoCA 2 signal, the transmitter is configured to transmit the MoCA 2 signal over the coax medium.

3. The apparatus of claim 1, further comprising a semiconductor chip, wherein:

the first and second channels are integral to the chip; and

the first channel is substantially parallel the second channel.

4. The apparatus of claim 1, wherein the first channel is on an identified MoCA band and the second channel is on the identified MoCA band.

5. The apparatus of claim 1, further comprising an oscillator, wherein:

the first channel is in communication with the oscillator;

the second channel is in communication with the oscillator;

the oscillator is configured to generate a timing signal;

the first channel transmits based on the timing signal; and

the second channel transmits based on the timing signal.

6. The apparatus of claim 5 wherein, when the first portion includes a first preamble and the second portion includes a second preamble:

the first channel is configured to transmit the first preamble in response to a trigger in the timing signal; and

the second channel is configured to transmit the second preamble in response to the trigger.

7. The apparatus of claim 1, wherein:

the first channel is configured to transmit the first portion at a first frequency;

the second channel is configured to transmit the second portion at a second frequency; and

the first frequency is different from the second frequency.

8. The apparatus of claim 1, further comprising a subcarrier mapper, wherein:

the subcarrier mapper is configured to define the first portion and the second portion based on bit loading.

9. The apparatus of claim 8 wherein:

the subcarrier mapper is configured to:

designate the first portion to a first subcarrier; and

designate the second portion to a second subcarrier; and

the first subcarrier corresponds to the first transmission channel; and

the second subcarrier corresponds to the second transmission channel.

10. The apparatus of claim 9 wherein the subcarrier mapper is configured to select, for each of the first and second portions, one of the first and second transmission channels.

11. The apparatus of claim 10 further comprising N −2 additional transmission channels, such that the apparatus comprises N total transmission channels;

wherein the subcarrier mapper is configured to select the first and second transmission channels from among the N total transmission channels.

12. The apparatus of claim 11 wherein N equals at least one of 3, 4, or 6.

13. The apparatus of claim 1, wherein the first channel includes a BIN scrambler.

14. The apparatus of claim 13 wherein the first channel includes an OFDM modulator.

15. The apparatus of claim 14 wherein the first channel includes a filter.

16. The apparatus of claim 1, wherein the second channel includes a BIN scrambler.

17. The apparatus of claim 16 wherein the second channel includes an OFDM modulator.

18. The apparatus of claim 17 wherein the second channel includes a filter.

19. The apparatus of claim 1, further comprising a preprocessor output buffer in communication with the physical layer frequency domain signal preprocessor.

20. The apparatus of claim 19 wherein the buffer is configured to store a first output from the preprocessor, the first output corresponding to the first portion of the signal.

21. The apparatus of claim 20 further comprising control logic that is configured to transfer the first output from the buffer to the first channel at substantially a same time as the physical layer frequency domain signal preprocessor transfers a second output to the second transmission channel, the second output corresponding to the second portion of the signal.

22. An apparatus for transmitting information over a coax network, the apparatus comprising:

a Media Access Control (MAC) layer interface configured to provide a first portion of information packets to a first physical layer time domain signal transmitter and a second portion of the information packets to a second physical layer time domain signal transmitter;

the first physical layer time domain signal transmitter configured to receive the first portion of the information packets from the MAC layer interface, convert the first portion of the information packets into a first signal, and transmit the first signal comprising the first portion of the information packets over the coax network via a first radio frequency transmission channel; and

the second physical layer time domain transmitter configured to receive the second portion of the information packets from the MAC layer interface, convert the first portion of the information packets into the first signal, and transmit the second signal comprising the second portion of the information packets over the coax network via a second radio frequency transmission channel,

wherein a first clock of the first physical layer transmitter and a second clock of the second physical layer transmitter are derived from a common reference frequency.

23. The apparatus of claim 22, wherein the first radio frequency transmission channel comprises a first 100 MHz transmission spectrum and the second radio frequency transmission channel comprises a second 100 MHz transmission spectrum that is proximal to, but non-overlapping with, the first 100 MHz transmission spectrum.

24. A method for transmitting information over a coax network, the method comprising:

receiving, by a physical layer frequency domain signal preprocessor, information packets and converting the information packets into a signal;

receiving the signal by a physical layer time domain signal transmitter from the physical layer frequency domain signal preprocessor; and

transmitting, by the physical layer time domain signal transmitter, a first portion of the signal over the coax network via a first radio frequency transmission channel comprising a first transmission spectrum and a second portion of the signal over the coax network via a second radio frequency transmission channel comprising a second transmission spectrum that is proximal to but non-overlapping with the first transmission spectrum.

25. The method of claim 24, wherein the first transmission spectrum and the second transmission spectrum comprise 100 MHz transmission spectrums.