Orthogonal frequency division multiplex modem circuit

• US 8,335,153 B2
• Filed: 10/27/2010
• Issued: 12/18/2012
• Est. Priority Date: 06/14/2000
• Status: Expired due to Term

• Current Assignee: Lenovo Innovations Ltd Hong Kong (Lenovo Group Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Ichihara, Masaki, Furuya, Yukitsuna
• Primary Examiner(s): PHUNKULH, BOB A
• Application Number:
  US12/913,266
• Publication Number:
  US 20110038403A1
• Time in Patent Office: 783 Days
• Field of Search: None
• US Class Current: 370/208
• CPC Class Codes: H04L 27/183 Multiresolution systems
• CPC Class Codes: H04L 27/2604 Multiresolution systems by means of multiresolution subcarriers H04L27/183, H04L27/3488
• CPC Class Codes: H04L 27/3488 Multiresolution systems
• 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
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/06 the signals being represented by different frequencies combined with time-division multiplexing H04L5/26

Abstract

To provide an orthogonal frequency division multiplex modem circuit which can multiplex signals, whose bit rates and QoS are different from one another, and can transmit the signals via one OFDM line. A serial/parallel converter converts input signals into a complex parallel signal respectively, and a sub carrier and a modulation system are assigned every communication channel. A randomizer changes the alignment sequence of the signal, a discrete inverse Fourier transformer processes the signal, a parallel/serial converter converts the signal into a serial signal, and a transmitter performs the orthogonal modulation of the signal to output the signal from an antenna. A receiver performs orthogonal demodulation of the signal received with an antenna, a serial/parallel converter converts the signal into a parallel signal, and a discrete Fourier transformer processes the parallel signal. In addition, a de-randomizer restores the alignment sequence of the subcarriers into the original condition, and a parallel/serial converter decodes and outputs the signal.

Claims

1. A transmitter for an orthogonal frequency division multiplex (OFDM) modem system which uses a plurality of subcarriers for communication and transmits and receives a plurality of communication channels, wherein said communication channels are adapted for transmitting and receiving with different bit rates, Quality of Service (QoS) and/or priorities, and wherein one or more subcarriers are assigned to each of a plurality of the communication channels and the number of the subcarriers assigned to each of said plurality of the communication channels is determined according to at least two of the bit rate, QoS and priority of the communication channel,

wherein the number of the subcarriers is determined such that the symbol rates of all subcarriers are set to the same rate, and

wherein the transmitter is configured to adaptively determine a number of communication channels transmitted by the OFDM modem system according to at least one of the bit rate, QoS and the priority.

2. The transmitter according to claim 1, wherein the assignment of the number of the subcarriers to the respective communication channels is adaptively performed.

3. A receiver for an orthogonal frequency division multiplex (OFDM) modem system which uses a plurality of subcarriers for communication and transmits and receives a plurality of communication channels, wherein said communication channels are adapted for transmitting and receiving with different bit rates, Quality of Service (QoS) and/or priorities, and wherein one or more subcarriers are assigned to each of a plurality of the communication channels and the number of the subcarriers assigned to each of said plurality of the communication channels is determined according to at least two of the bit rate, QoS and priority of the communication channel,

wherein the number of the subcarriers is determined such that the symbol rates of all subcarriers are set to the same rate, and

wherein a number of communication channels transmitted by the OFDM modem system is determined according to at least one of the bit rate, QoS and the priority.

4. The receiver according to claim 3, wherein the assignment of the number of the subcarriers to the respective communication channels is adaptively performed.

5. An orthogonal frequency division multiplex modem system comprising:

a transmitter in a transmission system for an orthogonal frequency division multiplex (OFDM) modem system which uses a plurality of subcarriers for communication and transmits and receives a plurality of communication channels, wherein said communication channels are adapted for transmitting and receiving with different bit rates, Quality of Service (QoS) and/or priorities, and wherein one or more subcarriers are assigned to each of a plurality of the communication channels and the number of the subcarriers assigned to each of said plurality of the communication channels is determined according to at least two of the bit rate, QoS and priority of the communication channel, wherein the number of the subcarriers is determined such that the symbol rates of all subcarriers are set to the same rate, and wherein the transmitter is configured to adaptively determine a number of communication channels transmitted by the OFDM modem system according to at least one of the bit rate, QoS and the priority; and

a receiver in a receiving system for an orthogonal frequency division multiplex modem system which uses a plurality of subcarriers for communication and transmits and receives a plurality of communication channels, wherein said communication channels are adapted for transmitting and receiving with different bit rates, QoS and/or priorities, and wherein one or more subcarriers are assigned to each of a plurality of the communication channels and the number of the subcarriers assigned to each of said plurality of the communication channels is determined according to at least two of the bit rate, QoS and priority of the communication channel.

6. A transmission method comprising:

providing an orthogonal frequency division multiplex (OFDM) communication system comprising a transmitter, which uses a plurality of subcarriers for communication and transmits and receives a plurality of communication channels, said communication channels transmitting and receiving with different bit rates, Quality of Service (QoS) and/or priorities, said transmitter performing the following steps;

assigning one or more subcarriers to each of a plurality of the communication channels;

determining the number of the subcarriers assigned to each of said plurality of the communication channels according to at least two of the bit rate, QoS and priority of the respective communication channel;

determining the number of the subcarriers such that the symbol rates of all subcarriers are set to the same rate; and

determining a number of communication channels transmitted by the OFDM communication system according to at least one of the bit rate, QoS and the priority.

7. The transmission method according to claim 6, comprising the step of adaptively assigning the number of the subcarriers to the respective communication channels.

8. A receiving method comprising:

providing an orthogonal frequency division multiplex (OFDM) communication system comprising a receiver, which uses a plurality of subcarriers for communication and transmits and receives a plurality of communication channels, said communication channels transmitting and receiving with different bit rates, Quality of Service (QoS) and/or priorities, said receiver performing the following steps;

assigning one or more subcarriers to each of a plurality of the communication channels;

determining the number of the subcarriers assigned to each of said plurality of the communication channels according to at least two of the bit rate, QoS and priority of the respective communication channel; and

determining the number of the subcarriers such that the symbol rates of all subcarriers are set to the same rate, wherein a number of communication channels transmitted by the OFDM communication system is determined according to at least one of the bit rate, QoS and the priority.

9. The receiving method according to claim 8, comprising the step of adaptively assigning the number of the subcarriers to the respective communication channels.

10. An orthogonal frequency division multiplex communication method comprising:

a transmission method comprising;

providing an orthogonal frequency division multiplex (OFDM) communication system comprising a transmitter, which uses a plurality of subcarriers for communication and transmits and receives a plurality of communication channels, said communication channels transmitting and receiving with different bit rates, Quality of Service (QoS) and/or priorities;

said transmitter performing the following steps;

assigning one or more subcarriers to each of a plurality of the communication channels; and

determining the number of the subcarriers assigned to each of said plurality of the communication channels according to at least two of the bit rate, QoS and priority of the respective communication channel, wherein the number of the subcarriers is determined such that the symbol rates of all subcarriers are set to the same rate, and wherein a number of communication channels transmitted by the OFDM communication system is determined according to at least one of the bit rate, QoS and the priority; and

a receiving method comprising;

providing an orthogonal frequency division multiplex communication system comprising a receiver, which uses a plurality of subcarriers for communication and transmits and receives a plurality of communication channels, said communication channels transmitting and receiving with different bit rates, QoS and/or priorities;

said receiver performing the following steps;

assigning one or more subcarriers to each of a plurality of the communication channels; and

determining the number of the subcarriers assigned to each of said plurality of the communication channels according to at least two of the bit rate, QoS and priority of the respective communication channel.