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G.hn

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ITU-T home networking recommendations
Common name Recommendations
HomePNA 2.0 G.9951, G.9952, G.9953
HomePNA 3.0 G.9954 (02/05)
HomePNA 3.1 G.9954 (01/07)
G.hn G.9960, G.9961
G.hn-management G.9962
G.hn-mimo G.9963
G.hn-psd G.9964
G.vlc G.9991
G.cx G.9972
G.hnta G.9970
G.dpm G.9977
G.sa G.9978
G.cwmp (TR-069) G.9980

G.hn is the common name for the "next generation" home network technology standard being developed under the International Telecommunication Union (ITU). The first Recommendation for G.hn is G.9960, which received consent on Dec 12th 2008. The work is being done in the ITU-T Telecommunication Standardization Sector, Study Group 15, Question 4. Over 20 companies are participating regularly representing a broad cross section of the communications industry including some of the worlds largest telephone companies, major communication equipment companies and some of the leading home networking technology companies.

Overview

G.hn is the next generation standard for existing-wire home networking (a wired and complementary counterpart to the popular WiFi wireless home networking standard). G.hn targets gigabit per second data rates and operation over all three types of home wires: coaxial, power lines and phone wires.

G.hn proponents are working to make G.hn the future universal wired home networking standard worldwide; coexisting with and providing an evolution path from today's existing-wire home networking technologies including Multimedia over Coax Alliance over coax, HomePNA 3.1 over coax and phone wires (already an ITU standard G.9954), and Homeplug AV, Universal Powerline Association (UPA) and HD-PLC over powerline.

Although the "killer" application for existing wire home network technologies is IPTV (especially IPTV offered by a service provider as part of a Triple play (telecommunications) video, voice and data service offering such as AT&T's U-Verse), it is expected that G.hn will also become the dominant wired networking standard for other markets such as the PC and CE industries.[1]

The promise of G.hn is one semiconductor device that can be used for networking over any home wire. Some benefits of the final standard are expected to be lower equipment development costs and lower deployment costs for service providers.

Technical specifications

Overview

G.hn specifies a single PHY based on FFT OFDM modulation and Low-Density Parity-Check (LDPC) FEC code. G.hn includes the capability to notch specific frequency bands to avoid interference with Amateur Radio bands and other licensed radio services. G.hn also includes mechanisms to avoid interference with other wireline systems such as VDSL2 or other types of DSL used to access the home.

The G.hn Medium Access Control is based on a TDMA architecture, in which a "domain master" schedules Transmission Opportunities (TXOPs) that can be used by one or more devices in the "domain". There are two types of TXOPs:

  • Contention-Free Transmission Opportunities (CFTXOP), which have a fixed duration and are allocated to a specific pair of transmitter and receiver. CFTXOP are used for implementing TDMA Channel Access for specific applications that require Quality of Service guarantees.
  • Shared Transmission Opportunities (STXOP), which are shared among multiple devices in the network. STXOP are divided into Time Slots (TS). There are two types of TS:
    • Contention-Free Time Slots (CFTS), which are used for implementing CSMA/CA Channel Access.
    • Contention-Based Time Slots (CBTS), which are used for implementing CSMA/CARP Channel Access.

G.hn uses the AES encryption algorithm to ensure security.

Protocol stack

G.hn protocol stack
G.hn protocol stack

G.hn specifies the Physical Layer and the Data Link Layer, according to the OSI model.[2]

  • The Physical Layer is divided into three sub-layers:
    • The Physical Coding Sub-layer (PCS), responsible for generating PHY headers.
    • The Physical Medium Attachment (PMA), responsible for scrambling and FEC coding/decoding.
    • The Physical Medium Dependent (PMD), responsible for bit-loading and OFDM modulation.

The PMD sub-layer is the only sub-layer in the G.hn stack that is "medium dependent" (ie, some parameters may have different values for each media - power lines, phone lines and coaxial cable). The rest of sub-layers (APC, LLC, MAC, PCS and PMA) are "medium independent".

Status

During 2008 the group completed a Foundation document which was then approved at the December 2008 Plenary meeting of Study Group 15.[3][4][5][6][7][8][9] The standard has been in development since 2006.

G.hn-compliant chips are expected during late 2009 or early 2010, with consumer products available shortly thereafter.[10]

Public Support

HomeGrid Forum

HomeGrid Forum is a global, non-profit trade group promoting the International Telecommunication Union’s G.hn standardization efforts for next-generation home networking.[11] HomeGrid Forum promotes adoption of G.hn through technical and marketing efforts, addresses certification and interoperability of G.hn-compliant products, and cooperates with complementary industry alliances.

HomeGrid Forum members include Intel, Infineon, Panasonic, Texas Instruments, Best Buy, Ikanos Communications, Aware, DS2, Gigle, Pulse~Link, ACN, Sigma Designs, Westell, University of New Hampshire InterOperability Laboratory (UNH-IOL) and LAN S.A.R.L.

Silicon and IP Vendors

Immediately after G.hn's consent, several vendors, including Aware[12], CopperGate[13], DS2[14] and Ikanos[15] announced support for the new G.hn standard.

Service Providers

On February 26th 2009, as part of a HomePNA press release, AT&T (which makes extensive use of wireline home networking as part of its U-Verse IPTV service) expressed support for the work developed by ITU-T creating standards for home networking, including G.hn.[16]

Service providers like AT&T will benefit from G.hn for several reasons[17]:

  • Connect to any room no matter what the wiring type may be.
  • Enable customer self-install
  • Built-in diagnostic information an remote management
  • Multiple silicon and equipment suppliers

Other Service Providers that are active contributors to the work being done by ITU-T Study Group 15, Question 4, include British Telecom, France Telecom, NTT, Telenor and Verizon.[18][19]

Consumer Electronics

On March 2009, Best Buy (which is the largest retailer of consumer electronics in the United States) joined the Board of Directors of HomeGrid Forum and expressed its support for G.hn technology as the single standard for wired home networks:[20][21]

“One of the greatest challenges facing consumers today is the many incompatible technologies that exist for wired networking in the home.[...] Best Buy supports the global adoption of the ITU-T’s G.hn next-generation technology as the single wired standard for connecting devices together over coax, powerlines, and phonelines in the home.”

Panasonic, one of the largest manufacturers of consumer electronics, is also a member of the Board of Directors of HomeGrid Forum.

Other Organizations

On February 25th 2009, three home networking organizations that promoted previously incompatible technologies (CEPCA, HomePNA and the Universal Powerline Association), announced that they had agreed to work with Homegrid Forum to promote G.hn as the single next-generation standard for wired home networking, and to work to ensure coexistence with existing products in the market.[22][23][24]

On October 2008, the Continental Automated Buildings Association (CABA) and HomeGrid Forum signed a liaison agreement to support HomeGrid Forum’s efforts in conjunction with ITU-T G.hn to make it easy for consumers worldwide to connect devices and enjoy innovative applications using existing home wiring.[25]

Shortly after G.9960 achieved consent, the IEEE P1901 group adopted a baseline (the first early stage in the development of an IEEE standard) that includes three non-interoperable options for PHY and MAC. One of the three PHY/MAC options, which was added in order to get a successful confirmation vote for the baseline text, is compatible with G.hn/G.9960. Although P1901 devices will not necessarily interoperate with each other (because of multiple incompatible PHY/MAC options), the subset of P1901 devices that implement the "G.hn compatible" PHY/MAC will interoperate with ITU-T G.hn devices.


References

  1. ^ Multiple industries converging around the G.hn standard, HomeGrid Forum Blog
  2. ^ HomeGrid Forum - G.hn Technology Overview, (registration required)
  3. ^ New global standard for fully networked home, ITU-T Press Release
  4. ^ G.hn hits milestone toward unified home nets, ITU approves physical layer spec, sparking chip work
  5. ^ New G.hn ITU Standard for Home Networks, PC World
  6. ^ New standard to wire up the digital home in the age of multimedia, iTWire
  7. ^ New standard brightens digital home vision, G.hn plans to simplify home networking but needs sexier name
  8. ^ ITU-T G.hn spec endorsed, The Telecom
  9. ^ The world relishes ITU’s new global standard for fully networked home, Vanguard Online
  10. ^ How To Save The Home Networking Industry, EDN
  11. ^ ITU-T G.hn Specification Achieves Key Milestone with Successful Consent at Geneva ITU-T Meeting, Significant Progress Towards Unified Standard for Home Networking Endorsed by HomeGrid Forum
  12. ^ Aware Applauds the ITU's Consent of a Revolutionary New Home Networking Technology
  13. ^ CopperGate Communications Commits to G.hn
  14. ^ DS2 welcomes new ITU-T G.hn standard for high-speed networking and plans for compatible chipset with G.hn/UPA/OPERA compatibility
  15. ^ Ikanos Communications Announces Support for International Telecommunications Union G.hn Consent
  16. ^ HomePNA and HomeGrid Sign Liaison Agreement, Groups Work to Promote New ITU G.hn Global Wired Home Networking Standard
  17. ^ AT&T Participating in G.hn Standard Development, Everywire, Your Definitive Source for All Things G.hn
  18. ^ ITU-T SG15 Q4 - Geneva December 2008
  19. ^ The Everywire Standard: G.hn and HomeGrid Forum, The BroadBand Home Report
  20. ^ HomeGrid Forum Adds New Members, Best Buy Joins Board Of Directors, Consumer Electronics Retailer to Help Drive G.hn Technology
  21. ^ HomeGrid and Best Buy - a logical marriage, Alliance focuses on making home networking more palatable for consumers
  22. ^ Home networking groups edge toward G.hn, EE Times
  23. ^ G.hn-ing for gigabit - How the next-gen home LAN standard war was won, The Register
  24. ^ UN’s ITU-T G.hn standard gains support
  25. ^ HomeGrid Forum and CABA Ink Liaison Agreement to Promote Development and Deployment of Advanced Intelligent Home Networks


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