ADSL modem apparatus and communication method thereof

{
  "publication_number": "US2005025086A1",
  "country": "US",
  "kind": "A1",
  "title": "ADSL modem apparatus and communication method thereof",
  "abstract": "A processor of a transceiver estimates a communication distance to an opposing ADSL modem apparatus by detecting a reception level of a REVERB signal in accordance with the ITU-T regulated G.992.1 or G. 992.2. Based on the estimated communication distance, and by referring to a table showing attenuation of signal energy (stored in a RAM), the signal energy in a high frequency band (among the signal energy assigned to transmitting signals) is concentrated into a low frequency band during the communication.",
  "claims": [
    "1. An ADSL modem apparatus comprising: an exchange unit that transmits and receives a REVERB signal according to one of the ITU-T standard G.992.1 and G.992.2; and an estimation unit that estimates a communication distance to an opposing ADSL modem apparatus according to a reception level of the REVERB signal. 2. The ADSL modem apparatus according to claim 1, wherein said estimation unit estimates the communication distance to the opposing ADSL modem apparatus by comparing reception levels of two carriers, the carriers being selected from a plurality of carriers that configure the REVERB signal. 3. The ADSL modem apparatus according to claim 1, further comprising: a communication unit that communicates by concentrating signal energy into a low frequency band, the signal energy being assigned to a transmission signal according to the communication distance estimated by said estimation unit. 4. The ADSL modem apparatus according to claim 3, wherein said communication unit minimizes the signal energy assigned to a high frequency band and increases the signal energy assigned to the low frequency band, when the communication distance to the opposing ADSL modem apparatus is increased. 5. The ADSL modem apparatus according to claim 1, wherein the ADSL modem apparatus is located at a remote side, and wherein the communication distance between the remote side ADSL modem apparatus and a center side ADSL modem apparatus is estimated. 6. The ADSL modem apparatus according to claim 1, wherein the ADSL modem apparatus is located at a center side, and wherein the communication distance between the center side ADSL modem apparatus and a remote side ADSL modem apparatus is estimated. 7. A communication method for an ADSL modem apparatus, the method comprising: receiving a REVERB signal according to one of the ITU-T standard G.992.1 and G.992.2; estimating a communication distance to an opposing ADSL modem apparatus according to a reception level of the REVERB signal; and concentrating signal energy into a low frequency band, the signal energy being assigned to a transmission signal according to the estimated communication distance. 8. The communication method for an ADSL modem apparatus according to claim 7, the method further comprising: minimizing the signal energy assigned to a high frequency band and increasing the signal energy assigned to the low frequency band, when the communication distance to the opposing ADSL modem apparatus is increased."
  ],
  "description_excerpt": "1. Field of the Invention The present invention relates to an ADSL modem apparatus an ADSL modem communication method. 2. Description of Related Art The ADSL communication realizes a high-speed data communication between ADSL modem apparatuses that are installed to both center side (telephone exchange) and remote side (subscriber). However, the ADSL communication that uses a frequency band between 10 kHz-1 MkHz has limitations in distance, since the attenuation rate at a high frequency range is large, thereby affecting the signal communication. In order to overcome such limitations, a technology has been disclosed that enables the signal communication distance to be extended (even with the large attenuation in the high frequency range). The extension method includes detecting gain characteristics of a signal received in accordance with an initialization sequence using the ADSL modem apparatuses of both center and remote sides, notifying each other of the gain characteristics, and correcting gain characteristics of transmitting signals in the future, based on the gain characteristics notified from the opposing side (e.g., Related Art 1).\n\n[Related Art 1] Japanese Patent Laid Open Publication 2003-87352 (FIGS. 4 and 5) However, even with the above described conventional art, maximum transfer rate is decreased in long distance communication, due to the attenuation and noise. In a normal setting, the communication distance cannot be longer than several km (5.5 km at 1.5 M bits/sec transfer; 1.8 km at 6M bits/sec transfer) from the center side (telephone exchange).",
  "cpc": [
    "H04L 1/0065",
    "B65C 1/02",
    "B65C 9/02",
    "B65C 9/1884",
    "B65C 9/40",
    "B65C 9/46",
    "B65G 15/20",
    "B65G 21/14",
    "H04L 1/0071",
    "H04L 27/2626",
    "H04L 27/2647",
    "H04L 5/0007",
    "H04L 5/0046",
    "H04L 5/006",
    "H04L 5/1438"
  ],
  "ipc": [
    "H04J 11/00",
    "H04L 1/00",
    "H04L 12/20",
    "H04L 27/26",
    "H04L 29/08",
    "H04L 5/14"
  ],
  "assignees": [
    "MATSUSHITA ELECTRIC INDUSTRIAL CO LTD"
  ],
  "inventors": [
    "NOMA NOBUHIKO",
    "TAKAGI GENZO",
    "NAGAI MOTOYOSHI",
    "ARAKI MITSUHIRO",
    "ATSUTA AKIRA"
  ],
  "filing_date": "2004-02-06",
  "publication_date": "2005-02-03",
  "priority_date": "2003-08-01",
  "application_number": "US-77230804-A",
  "family_id": "33535741",
  "citations": [
    "US2003108191A1",
    "US2004022270A1",
    "US25227A",
    "US31027A",
    "US41729A",
    "US41730A",
    "US6566889B2",
    "US6765989B1"
  ]
}