Method and apparatus for transmitting data based on OFDM

Abstract

Provided is a method and apparatus for transmitting data based on OFDM (Orthogonal Frequency Division Multiplexing). The method includes: forming a plurality of packets suitable for a selected transmission mode from data input to a transmitter; determining a transfer rate of the data; when the data transfer rate is determined to be low and synchronous connection oriented link should be maintained, dividing each of the plurality of packets into a plurality of sub-packets; and transmitting the divided sub-packets, wherein when the divided sub-packets are transmitted, a power supply duration of the transmitter is reduced by using a DPM (dynamic power management) or fine state control unit.

What is claimed is: 
     
       1. A method for transmitting data based on OFDM (Orthogonal Frequency Division Multiplexing), the method comprising the steps of:
 forming a plurality of packets suitable for a selected transmission mode from data input to a transmitter;   determining a transfer rate of the data and required quality of service;   when a data transfer rate is determined to be low and a synchronous connection oriented link should be maintained, dividing each of the packets into a plurality of divided sub-packets, wherein a power supply duration of the transmitter is reduced from a transmission end time of each of the divided sub-packets to a transmission start time of a next sub-packet; and   transmitting the divided sub-packets, wherein when the divided sub-packets are transmitted, the power supply duration of the transmitter is reduced.   
     
     
       2. The method according to  claim 1 , further comprising the step of: when the data transfer rate is determined to be high, transmitting the packets without division. 
     
     
       3. The method according to  claim 1 , wherein the low data transfer rate is less than 10 Mb/s. 
     
     
       4. The method according to  claim 1 , wherein the packets are formed to be suitable for a 16-QAM (Quadrature Amplitude Keying) OFDM 1 Gb/s transmission mode. 
     
     
       5. An apparatus for transmitting data based on Orthogonal Frequency Division Multiplexing (OFDM), the apparatus comprising:
 a packet configuration unit for forming a plurality of packets suitable for a selected transmission mode from payload data generated in an upper application layer and a MAC (Media Access Control) layer and storing the plurality of packets therein;   a packet dividing unit for, when it is determined that a transfer rate of the stored packets is low, dividing each of the plurality of packets into a plurality of sub-packets;   a modulating unit for OFDM-modulating the payload data of the packets or the sub-packets;   an analog/RF unit for converting the modulated signal into an analog signal and RF-transmitting the converted analog signal; and   a fine state controlling unit or dynamic power management (DPM) unit for, when the sub-packets are transmitted, reducing a power supply duration of the modulating unit and the analog/RF unit, wherein the fine slate controlling unit reduces the power supply duration of the modulating unit and the analog/RE unit from a transmission end time of each of the sub-packets to a transmission start time of a next sub-packet.   
     
     
       6. The apparatus according to  claim 5 , wherein when the packet dividing unit determines the transfer rate to be high, the packets formed in the packet configuration unit are transmitted without division. 
     
     
       7. The apparatus according to  claim 5 , wherein the packet dividing unit adds a preamble to the sub-packets and generates the sub-packets having a predetermined interval. 
     
     
       8. A method for transmitting data, the method comprising:
 forming packets from input data;   determining a transfer rate of the data;   dividing each of the packets into a plurality of sub-packets in case the transfer rate is determined to be lower than a reference rate;   transmitting the packets in case the transfer rate is determined to be higher than the reference rate; and   transmitting the sub-packets in case the transfer rate is determined to be lower than the reference rate,   wherein the transmission of the sub-packets includes active states consuming a first transmission power and inactive states consuming a second transmission power lower than the first transmission power, and   wherein power consumption of a transmitter is reduced from a transmission end time of each of the divided sub-packets to a transmission start time of a next sub-packet.    
     
     
       9. A method for transmitting data, the method comprising:
 forming packets from input data;   determining a transfer rate of the data;   dividing each of the packets into a plurality of sub-packets in case the transfer rate is determined to be lower than a reference rate;   transmitting the packets in case the transfer rate is determined to be higher than the reference rate; and   transmitting the sub-packets in case the transfer rate is determined to be lower than the reference rate,   wherein the transmission of the sub-packets includes active states consuming a first transmission power and inactive states consuming a second transmission power lower than the first transmission power, and   wherein an inactive state corresponds to a duration from a transmission end time of a sub-packet to a transmission start time of a next sub-packet.    
     
     
       10. A method for transmitting data, the method comprising:
 forming packets from input data;   determining a transfer rate of the data;   dividing each of the packets into a plurality of sub-packets in case the transfer rate is determined to be lower than a reference rate;   transmitting the packets in case the transfer rate is determined to be higher than the reference rate; and   transmitting the sub-packets in case the transfer rate is determined to be lower than the reference rate,   wherein the transmission of the sub-packets includes active states consuming a first transmission power and inactive states consuming a second transmission power lower than the first transmission power, and   wherein a total active state duration corresponding to the total duration of the active states is shorter than an operating state duration corresponding to the transmission of the packets.    
     
     
       11. An apparatus for transmitting data, the apparatus comprising:
 a packet forming unit configured to form packets from input data;   a packet dividing unit configured to divide each of the packets into a plurality of sub-packets in case a transfer rate of the data is lower than a reference rate; and   a transmission unit configured to transmit the packets in case the transfer rate is higher than the reference rate and configured to transmit the sub-packets in case the transfer rate is lower than the reference rate;   wherein operation of the transmission unit for transmitting the sub-packets includes active states and inactive states and the transmission unit consumes less power during the inactive states than during the active states, and   wherein power consumption of the transmission unit is reduced from a transmission end time of each of the divided sub-packets to a transmission start time of a next sub-packet.    
     
     
       12. The apparatus according to claim 11, wherein the transmission unit comprises:
 a modulation unit configured to modulate the packets or the sub-packets; and   a RF unit configured to transmit the modulated packets or the modulated sub-packets,   wherein the RF unit consumes less power for transmitting the sub-packets than for transmitting the packets by reducing or shutting down power during the inactive states.    
     
     
       13. A method for transmitting data, the method comprising:
 forming packets from input data;   determining a transfer rate of the data;   dividing each of the packets into a plurality of sub-packets in case the transfer rate is determined to be lower than a reference rate;   transmitting the packets in case the transfer rate is determined to be higher than the reference rate; and   transmitting the sub-packets in case the transfer rate is determined to be lower than the reference rate,   wherein the transmission of the sub-packets includes active states consuming a first transmission power and inactive states consuming a second transmission power lower than the first transmission power, and   wherein transmission power is decreased from the first transmission power to the second transmission power at a transmission end time of each of the divided sub-packets and transmission power is increased from the second transmission power to the first transmission power at a transmission start time of a next sub-packet.