Communication system, communication terminal and communication method

• US 20030129978A1
• Filed: 11/19/2002
• Published: 07/10/2003
• Est. Priority Date: 11/27/2001
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Konya, Satoshi, Akiyama, Keiji
• Granted Patent: US 6,985,714 B2
• Time in Patent Office: Days
• US Class Current: 455/426.1
• CPC Class Codes: H04B 2203/5441 Wireless systems or telephone
• CPC Class Codes: H04B 2203/5445 Local network
• CPC Class Codes: H04B 2203/5495 having measurements and testing channel
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0017 where the mode-switching is based on Quality of Service requirement
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 1/203 Details of error rate determination, e.g. BER, FER or WER
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability
• CPC Class Codes: H04L 12/5692 Selection among different networks
• CPC Class Codes: H04M 1/725 Cordless telephones user interfaces specially adapted therefor H04M1/724
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding
• CPC Class Codes: H04W 76/10 Connection setup

Abstract

From an electric pole outside to a cordless handset inside a building/facility, a communication line is established via an electric power line. At this point, it is judged whether or not electric power line communication is possible, and if electric power line communication is possible, the communication line between the cordless handset and a base unit is switched to an electric power line communication system, and a communication line is formed via an optical fiver cable from the electric power line. By measuring the communication quality levels of all lines of the wireless and electric power lines, the communication line having the highest communication quality level may be selected.

Claims

1. A communication system for communicating with a communication partner by selectively switching between a wireless communication system for communicating via a wireless line and a wired communication system for communicating via an electric power line for supplying electric power to a communication terminal, wherein

said communication system detects communication qualities of said wireless communication system and said wired communication system, and switches to the communication system having a better communication quality.

2. The communication system according to claim 1, wherein

said communication system detects a signal quality of said wireless communication system during communication via said wired communication system, and if the communication quality of said wireless communication system is at or above a predetermined level, said communication system switches from said wired communication system to said wireless communication system.

3. A communication terminal for communicating with a communication partner by selectively switching between a wireless communication system for communicating via a wireless line and a wired communication system for communicating by transmitting a signal via an electric power line for supplying electric power, comprising:

communication quality detecting means for detecting communication qualities of said wireless communication system and said wired communication system; and

switch means for selectively switching between said wireless communication system and said wired communication system on the basis of a judgment result of said communication quality detecting means.

4. The communication terminal according to claim 3, further comprising:

untransmitted data transmitting means for judging whether or not there is untransmitted data in a process of switching between said wireless communication system and said wired communication system by said switch means, and transmitting the untransmitted data after communication system switching is complete if there is untransmitted data.

5. The communication terminal according to claim 3, wherein

if said communication partner connected to said wireless communication system judges during communication via said wireless communication system that the communication quality of said wired communication system is good, said communication quality detecting means conducts a communication negotiation with said communication partner, and enables switching from said wireless communication system to said wired communication system.

6. The communication terminal according to claim 3, wherein

if said communication partner connected to said wireless communication system judges during communication via said wireless communication system that the communication quality of said wired communication system is low, said communication quality detecting means selects a different wired communication system line in accordance with a predetermined routing rule, and switches from said wireless communication system to said wired communication system using said different wired communication system line.

7. The communication terminal according to claim 3, wherein

when a communication failure occurs in said wireless communication system due to interference from another communication system, said communication terminal switches from said wireless communication system to said wired communication system by said electric power line.

8. The communication terminal according to claim 7, wherein

if a communication failure occurs in said wireless communication system, said communication terminal switches from said wireless communication system to said wired communication system at or within a predetermined time.

9. The communication terminal according to claim 3, wherein

said wireless communication system and said wired communication system are categorized into a plurality of communication modes having different data transmission rates, and

a communication mode having the highest communication quality is selected from said plurality of communication modes.

10. The communication terminal according to claim 9, further comprising:

processing means for calculating an average value of throughput shift for each of said communication modes by measuring throughput, which is the data transmission amount per unit time, a plurality of times;

storage means for storing in a table said average value of throughput shift calculated by said processing means; and

judging means for judging the highest average value of throughput shift by comparing said average value of throughput shift corresponding to each of said communication modes stored in said table of said storage means, wherein

said wireless communication system includes a wireless processing unit,

said wired communication system includes an electric power line carrier communication processing unit, and

said judging means uses said average value of throughput shift as a criterion for judging the communication quality level, and a communication mode corresponding to said highest average value of throughput shift is selected.

11. The communication terminal according to claim 9, further comprising:

processing means for calculating an average value of relative noise level shift based on the difference between an average value of noise level shift obtained by averaging a plurality of measurements of noise level per unit frequency and a reference noise level;

storage means for storing in a table said average value of relative noise level shift calculated by said processing means; and

judging means for judging the lowest average value of relative noise level shift by comparing said average value of relative noise level shift corresponding to each of said communication modes stored in said table of said storage means, wherein

said wireless communication system includes a wireless processing unit,

said wired communication system includes an electric power line carrier communication processing unit, and

said judging means uses said average value of relative noise level shift as a criterion for judging the communication quality level, and a communication mode corresponding to said lowest average value of relative noise level shift is selected.

12. The communication terminal according to claim 9, further comprising:

processing means for calculating an average value of relative delay spread shift based on the difference between an average value of delay spread shift obtained by averaging a plurality of measurements of delay spread shift, which is a standardized deviation of a propagation electric power density distribution on a time axis, and a reference delay spread;

storage means for storing in a table said average value of relative delay spread shift calculated by said processing means; and

judging means for judging the lowest average value of relative delay spread shift by comparing said average value of relative delay spread shift corresponding to each of said communication modes stored in said table of said storage means, wherein

said wireless communication system includes a wireless processing unit,

said wired communication system includes an electric power line carrier communication processing unit, and

said judging means uses said average value of relative delay spread shift as a criterion for judging the communication quality level, and a communication mode corresponding to said lowest average value of delay spread shift is selected.

13. The communication terminal according to claim 9, further comprising:

processing means for calculating one of a number of dip points at which a received power falls below a predetermined power level across at least a predetermined frequency width and a total value of frequency widths of said dip points;

storage means for storing in a table said one of said number of dip points and said total value of frequency widths calculated by said processing means as a dip level; and

judging means for judging the lowest dip level by comparing said dip level corresponding to each of said communication modes stored in said table of said storage means, wherein

said wireless communication system includes a wireless processing unit,

said wired communication system includes an electric power line carrier communication processing unit, and

said judging means uses said dip level as a criterion for judging the communication quality level, and a communication mode corresponding to said lowest dip level is selected.

14. The communication terminal according to claim 9, further comprising:

processing means for calculating an average value of packet error rate shift for each of said communication modes based on a plurality of measurements of a packet error rate, which expresses a ratio of packets which fail in transmission to transmitted packets;

storage means for storing in a table said average value of packet error rate shift calculated by said processing means; and

judging means for judging the lowest average value of packet error rate shift by comparing said average value of packet error rate shift corresponding to each of said communication modes stored in said table of said storage means, wherein

said wireless communication system includes a wireless processing unit,

said wired communication system includes an electric power line carrier communication processing unit, and

said judging means uses said average value of packet error rate shift as a criterion for judging the communication quality level, and a communication mode corresponding to said lowest average value of packet error rate shift is selected.

15. A communication terminal according to claim 9, further comprising:

processing means for calculating an average value of bit error rate shift for each of said communication modes based on a plurality of measurements of a bit error rate, which expresses a ratio of a bit amount of data which fails in transmission to a bit amount of transmitted data;

storage means for storing in a table said average value of bit error rate shift calculated by said processing means; and

judging means for judging the lowest average value of bit error rate shift by comparing said average value of bit error rate shift corresponding to each of said communication modes stored in said table of said storage means, wherein

said wireless communication system includes a wireless processing unit,

said wired communication system includes an electric power line carrier communication processing unit, and

said judging means uses said average value of bit error rate shift as a criterion for judging the communication quality level, and a communication mode corresponding to said lowest average value of bit error rate shift is selected.

16. A communication method for communicating between a communication terminal and a communication partner by selectively switching between a wireless communication system for communicating by transmitting a radio signal via a wireless line and a wired communication system for communicating by transmitting a signal via an electric power line for supplying electric power to said communication terminal, comprising:

detecting a communication quality of each of said wireless communication system and said wired communication system; and

selectively switching between said wireless communication system and said wired communication system on the basis of a judgment result of said detecting of the communication quality.

17. The communication method according to claim 16, further comprising:

judging whether or not there exists untransmitted data in the process of said selective switching of the communication system, and transmitting said untransmitted data when said switching of the communication system is complete if said untransmitted data exists.

18. The communication method according to claim 16, wherein

if, during communication by said wireless communication system, it is judged that the communication quality of communication by said wired communication system between said communication partner is good in said detecting of the communication quality of each of said wireless and wired communication systems,

in said selective switching of the communication system, said communication terminal conducts a communication negotiation with said communication partner to switch from said wireless communication system to said wired communication system.

19. The communication method according to claim 16, wherein

in said detecting of the communication quality, if it is judged that the communication quality of communication by said wired communication system between said communication partner is bad,

in said selective switching of the communication system, a wired communication system line by another electric power line is selected in accordance with a predetermined routing rule to switch from said wireless communication system to said wired communication system using said wired communication system line by said other electric power line.

20. The communication method according to claim 16, wherein

when a communication failure occurs in said wireless communication system due to interference from another communication system, a switch to said wired communication system is performed in said selective switching of the communication system.

21. The communication method according to claim 16, wherein

when a communication failure occurs in said wireless communication system, said wireless communication terminal is switched to said wired communication system within a predetermined time in said selective switching of the communication system.

22. The communication method according to claim 16, wherein

said wireless communication system and said wired communication system are categorized into a plurality of communication modes having different data transmission rates, and

a communication mode having the best communication quality is selected from said plurality of communication modes.

23. The communication method according to claim 22, further comprising:

calculating an average value of throughput shift for each of said communication modes by measuring throughput, which is the data transmission amount per unit time, a plurality of times;

storing said average value of throughput shift in a table;

judging a highest average value of throughput shift by comparing said average value of throughput shift corresponding to each of said plurality of communication modes stored in said table; and

selecting a communication mode corresponding to said highest average value of throughput shift using said average value of throughput shift as a criterion for judging said communication quality level, wherein

said wireless communication system comprises a wireless processing unit, and

said wired communication system comprises an electric power line carrier communication processing unit.

24. The communication method according to claim 22, further comprising:

calculating an average value of relative noise level shift for each of said communication modes based on the difference between an average value of noise level shift obtained by averaging a plurality of measurements of noise level per unit frequency and a reference noise level;

storing said average value of relative noise level shift in a table;

judging a lowest average value of relative noise level shift by comparing said average value of relative noise level shift corresponding to each of said plurality of communication modes stored in said table; and

selecting a communication mode corresponding to said lowest average value of relative noise level shift using said average value of relative noise level shift as a criterion for judging said communication quality level, wherein

said wireless communication system comprises a wireless processing unit, and

said wired communication system comprises an electric power line carrier communication processing unit.

25. The communication method according to claim 22, further comprising:

calculating an average value of relative delay spread shift for each of said communication modes based on the difference between an average value of delay spread shift obtained by averaging a plurality of measurements of delay spread, which is a standardized deviation of a propagation electric power density distribution on a time axis, and a reference spread shift;

storing said average value of relative delay spread shift in a table;

judging a lowest average value of relative delay spread shift by comparing said average value of relative delay spread shift corresponding to each of said plurality of communication modes stored in said table; and

selecting a communication mode corresponding to said lowest average value of relative delay spread shift using said average value of relative delay spread shift as a criterion for judging said communication quality level, wherein

said wireless communication system comprises a wireless processing unit, and

said wired communication system comprises an electric power line carrier communication processing unit.

26. The communication method according to claim 22, further comprising:

calculating one of a number of dip points, at which a received power falls below a predetermined power level across at least a predetermined frequency width, and a total value of frequency widths of said dip points;

storing said one of said number of dip points and said total value of said frequency widths in a table as a dip level;

judging a lowest dip level by comparing said dip level corresponding to each of said plurality of communication modes stored in said table; and

selecting a communication mode corresponding to said lowest dip level using said dip level as a criterion for judging said communication quality level, wherein

said wireless communication system comprises a wireless processing unit, and

said wired communication system comprises an electric power line carrier communication processing unit.

27. The communication method according to claim 22, further comprising:

calculating an average value of packet error rate shift for each of said communication modes based on a plurality of measurements of a packet error rate, which represents a ratio of packets that fail in transmission to transmitted packets;

storing said average value of packet error rate shift in a table;

judging a lowest average value of packet error rate shift by comparing said average value of packet error rate shift corresponding to each of said plurality of communication modes stored in said table; and

selecting a communication mode corresponding to said lowest average value of packet error rate shift using said average value of packet error rate shift as a criterion for judging said communication quality level, wherein

said wireless communication system comprises a wireless processing unit, and

said wired communication system comprises an electric power line carrier communication processing unit.

28. The communication method according to claim 22, further comprising:

calculating an average value of bit error rate shift for each of said communication modes based on a plurality of measurements of a bit error rate, which represents a ratio of a bit amount of data that fails in transmission to a bit amount of transmitted data;

storing said average value of bit error rate shift in a table;

judging a lowest average value of bit error rate shift by comparing said average value of bit error rate shift corresponding to each of said plurality of communication modes stored in said table; and

selecting a communication mode corresponding to said lowest average value of bit error rate shift using said average value of bit error rate shift as a criterion for judging said communication quality level, wherein

said wireless communication system comprises a wireless processing unit, and

said wired communication system comprises an electric power line carrier communication processing unit.