COMMUNICATION NETWORK SYSTEM, AND TRANSMISSION/RECEPTION APPARATUS, METHOD AND INTEGRATED CIRCUIT FOR USE THEREIN

• US 20090279638A1
• Filed: 07/17/2009
• Published: 11/12/2009
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: Akio Kurobe, Hisao Koga, Masahiro Maki, Mutsuhiko Oishi, Shigeo Yoshida, Tomohiro Kimura, Toshiyuki Wakisaka, Yuji Igata
• Original Assignee: Akio Kurobe, Hisao Koga, Masahiro Maki, Mutsuhiko Oishi, Shigeo Yoshida, Tomohiro Kimura, Toshiyuki Wakisaka, Yuji Igata
• Inventors: KUROBE, Akio, Koga, Hisao, Maki, Masahiro, Oishi, Mutsuhiko, Wakisaka, Toshiyuki, Yoshida, Shigeo, Igata, Yuji, Kimura, Tomohiro
• Granted Patent: US 7,924,940 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 27/0004 using wavelets
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling

Abstract

A communication network system sets communication parameters which enable an operation under a maximum possible communication rate in a situation where a transmission path has cyclic noise/impedance fluctuations. A transmission/reception apparatus 100 transmits training packets for checking the state of the power line at two distinct points in time. A transmission/reception apparatus analyzes SNR at each carrier frequency, and stores an SNR evaluation result. The transmission/reception apparatus compares two SNR evaluation results which are obtained through two instances of a channel estimation algorithm, selects an SNR evaluation result which dictates a faster PHY rate, and transmits it to the transmission/reception apparatus. The transmission/reception apparatus changes modulation/demodulation rules based on the received SNR analytical result.

Claims

1. A transmitting apparatus for transmitting input data to a receiving apparatus via a transmission path, comprising:

a transmitting section configured to generate a first training signal and a second training signal by modulating a plurality of carriers respectively having different frequencies and to transmit the first training signal and the second training signal to the receiving apparatus for estimating transmission conditions on a channel fluctuating cyclically;

a receiving section configured to receive, from the receiving apparatus, a first channel estimation result including a first tone map which indicates a modulation method for each carrier and is determined based on the first training signal, and a second channel estimation result including a second tone map which indicates a modulation method for each carrier and is determined based on the second training signal;

a storage section configured to store the first tone map and the second tone map; and

a control section configured to control a timing of transmission of the second training signal such that a time interval between transmissions of the first training signal and the second training signal is unequal to a cycle of channel fluctuation,

wherein said transmitting section transmits the input data by modulating the plurality of carriers according to the first tone map or the second tone map stored in said storage section.

2. The transmitting apparatus according to claim 1, wherein,

said control section is further configured to calculate a communication rate in a physical layer when using each of the first tone map and the second tone map, and to select one of the first tone map and the second tone map that dictates a maximum communication rate as a tone map to be used in said transmitting section for transmitting the input data.

3. The transmitting apparatus according to claim 1, wherein,

said control section is further configured to calculate a throughput provided for an upper layer when using each of the first tone map and the second tone map, and to select one of the first tone map and the second tone map that dictates a maximum throughput as a tone map to be used in said transmitting section for transmitting the input data.

4. The transmitting apparatus according to claim 1, wherein,

the first tone map is derived by calculating a signal-to-noise ratio with respect to a frequency of each carrier, based on the first training signal, and by allocating, for any carriers having a signal-to-noise ratio which is equal to or greater than a predetermined threshold value, a modulation method in accordance with a value of each signal-to-noise ratio, and by ensuring that any carriers having a signal-to-noise ratio which is less than the predetermined threshold value is not used, and

the second tone map is derived by calculating a signal-to-noise ratio with respect to the frequency of each carrier, based on the second training signal, and by allocating, for any carriers having a signal-to-noise ratio which is equal to or greater than the predetermined threshold value, and modulation method in accordance with the value of each signal-to-noise ratio, and by ensuring that any carriers having a signal-to-noise ratio which is less than the predetermined threshold value is not used.

5. The transmitting apparatus according to claim 1, wherein said transmitting section is further configured to retransmit data if the data is not correctly received by the receiving apparatus.

6. The transmitting apparatus according to claim 1, wherein,

the transmission path is a power line to which commercial electric power is applied, and

said control section is further configured to control the timing of transmission of the second training signal such that a time interval between transmission of the first training signal and the second training signal is unequal to an integer multiple of half the cycle of the commercial electric power.

7. A transmitting method, executed by a transmitting apparatus, for transmitting input data to a receiving apparatus via a transmission path, comprising the steps of:

generating a first training signal and a second training signal by modulating a plurality of carriers respectively having different frequencies for estimating transmission conditions on a channel fluctuating cyclically;

controlling a timing of transmission of the second training signal such that a time interval between transmissions of the first training signal and the second training signal is unequal to a cycle of channel fluctuation;

transmitting the first training signal and the second training signal to the receiving apparatus;

receiving, from the receiving apparatus, a first channel estimation result including a first tone map which indicates a modulation method for each carrier and is determined based on the first training signal, and a second channel estimation result including a second tone map which indicates a modulation method for each carrier and is determined based on the second training signal;

storing the first tone map and the second tone map; and

transmitting the input data by modulating the plurality of carriers according to the first tone map or the second tone map stored in the storing step.

8. An integrated circuit to be used in a transmitting apparatus for transmitting input data to a receiving apparatus via a transmission path, comprising:

a transmitting section configured to generate a first training signal and a second training signal by modulating a plurality of carriers respectively having different frequencies and to transmit the first training signal and the second training signal to the receiving apparatus for estimating transmission conditions on a channel fluctuating cyclically;

a receiving section configured to receive, from the receiving apparatus, a first channel estimation result including a first tone map which indicates a modulation method for each carrier and is determined based on the first training signal, and a second channel estimation result including a second tone map which indicates a modulation method for each carrier and is determined based on the second training signal;

a storage section configured to store the first tone map and the second tone map; and

a control section configured to control a timing of transmission of the second training signal such that a time interval between transmissions of the first training signal and the second training signal is unequal to a cycle of channel fluctuation,

wherein said transmitting section transmits the input data by modulating the plurality of carriers according to the first tone map or the second tone map stored in said storage section.