Modulating and coding apparatus and method in a high-rate wireless data communication system

• US 20050157803A1
• Filed: 01/21/2005
• Published: 07/21/2005
• Est. Priority Date: 01/20/2004
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Min-Goo, Gu, Young-Mo, Ha, Sang-Hyuck
• Application Number:
  US11/038,181
• Publication Number:
  US 20050157803A1
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• 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

An apparatus and method for determining a modulation order of packet data to be transmitted through a subcarrier in a transmission apparatus. In the apparatus and method, transmitter physical channels encode and modulate data to transmit the user data with OFDM symbols. A controller outputs packet data to the transmitter physical channels, and determines the number of transmission slots, the number of OFDM symbols, the number of subchannels, and a size of an encoder packet. A modulation order and code rate decider receives, from the controller, the number of transmission slots, the number of OFDM symbols, the number of subchannels, and a size of an encoder packet, calculates a Modulation order Product code Rate (MPR), determines a modulation order according to the MPR, and outputs the determined modulation order to a corresponding physical channel.

Claims

1. An apparatus for determining a modulation order of packet data to be transmitted through a plurality of subchannels, the apparatus comprising:

a controller for determining a number of OFDM symbols to be transmitted, the number of subchannels and a size of an encoder packet; and

a modulation order decider for calculating a Modulation order Product code Rate (MPR), for each packet data to be transmitted to each of the users, based on the determined number of OFDM symbols, the determined number of subchannels and the determined size of an encoder packet and determining a modulation order according to the MPR.

2. The apparatus of claim 1, wherein the modulation order decider determines a code rate based on the modulation order and the MPR

3. The apparatus of claim 1, wherein the modulation order decider determines a puncturing/repetition parameter based on the modulation order and the MPR.

4. The apparatus of claim 1, wherein the modulation order decider includes a table for storing code rates, modulation orders and the number of subchannels, all of which are determined based on the number of OFDM symbols to be transmitted, the number of subchannels, and a size of an encoder packet.

5. The apparatus of claim 1, wherein the MPR is calculated by

$\mathrm{MPR}=\frac{N_{\mathrm{EP}}}{N_{\mathrm{MS}}\times }$

N SCH ×

N OS

where N_SCH denotes the number of subchannels, N_OS denotes the number of OFDM symbols allocated per slot, N_EP denotes the number of encoder packets, and N_MS denotes the number of modulation symbols allocated to a channel resource comprised of one slot and one subchannel.

6. The apparatus of claim 1, wherein when packet data to be transmitted to a particular user is transmitted for two or more slots and has a different number of subchannels for each slot, the MPR is calculated by

$\mathrm{MPR}=\frac{N_{\mathrm{EP}}}{N_{\mathrm{MS}}\times }$

∑

k = 1 N slot ⁢

N SCH , k

where N_SCH,k denotes the number of subchannels allocated to a k^th slot, N_EP denotes the number of encoder packets, and N_MS denotes the number of modulation symbols allocated to a channel resource comprised of one slot and one subchannel.

7. The apparatus of claim 1, wherein when packet data to be transmitted to a particular user does not occupy all subcarriers for one slot during its transmission, the MPR is calculated by

$\mathrm{MPR}=\frac{N_{\mathrm{EP}}}{\sum _{}^{}}$

k = 1 N slot ⁢

∑

j N SCH , k ⁢

∑

i = 1 N OS , kj ⁢

N SCH

where N_OS,k,j denotes the total number of OFDM symbols allocated to a k^th slot and a j^th subchannel, N_SCH,k denotes the number of subchannels allocated to a k^th slot, N_EP denotes the number of encoder packets, and N_slot denotes the number of slots.

8. The apparatus of claim 1, wherein the modulation order is determined according to a predetermined value based on the calculated MPR.

10. The apparatus of claim 2, wherein the code rate is calculated by

code rate(R)=MPR/MO

where MO denotes a modulation order.

9. An apparatus for determining a modulation order of packet data to be transmitted through a plurality of subchannels, the apparatus comprising:

a controller for determining the number of OFDM symbols to be transmitted, the number of subchannels and a size of an encoder packet; and

a modulation order decider for calculating a Modulation order Product code Rate (MPR), for each packet data to be transmitted to each of the users, based on the determined number of OFDM symbols, the determined number of subchannels and the determined size of an encoder packet and determining a modulation order according to the MPR, wherein QPSK(modulation order

     2) is used if 0<

MPR<

1.5.

11. An apparatus for determining a modulation order of packet data to be transmitted through a plurality of subchannels, the apparatus comprising:

a controller for determining a number of OFDM symbols to be transmitted, the number of subchannels and a size of an encoder packet; and

a modulation order decider for calculating a Modulation order Product code Rate (MPR), for each packet data to be transmitted to each of the users, based on the determined number of OFDM symbols, the determined number of subchannels and the determined size of an encoder packet and determining a modulation order according to the MPR, wherein the MPR is calculated by

$\begin{array}{c}\mathrm{MPR}=\left(\mathrm{EP}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{size}\right)/\left(\mathrm{payload}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{modulation}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{symbols}\right)\\ =\left(\mathrm{EP}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{size}\right)/\left(48\times <br><br>\left(\mathrm{the}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{number}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{of}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{subchannel}\right)\right)\end{array}$

12. A method for determining a modulation order of packet data to be transmitted through a plurality of subcarriers, the method comprising the steps of:

determining the number of OFDM symbols to be transmitted, the number of subchannels and a size of an encoder packet;

calculating a Modulation order Product code Rate (MPR) for packet data to be transmitted based on the number of OFDM symbols to be transmitted, the number of subchannels, and the size of an encoder packet; and

determining the modulation order according to the calculated MPR.

13. The method of claim 12, wherein the MPR is calculated by

$\mathrm{MPR}=\frac{N_{\mathrm{EP}}}{N_{\mathrm{MS}}\times }$

N SCH ×

N OS

where N_SCH denotes the number of subchannels, N_OS denotes the number of OFDM symbols allocated per slot, N_EP denotes the number of encoder packets, and N_MS denotes the number of modulation symbols allocated to a channel resource comprised of one slot and one subchannel.

14. The method of claim 12, wherein when packet data to be transmitted to a particular user is transmitted for two or more slots and has a different number of subchannels for each slot, the MPR is calculated by

$\mathrm{MPR}=\frac{N_{\mathrm{EP}}}{N_{\mathrm{MS}}\times }$

∑

k = 1 N slot ⁢

N SCH , k

where N_SCH,k denotes the number of subchannels allocated to a k^th slot, N_EP denotes the number of encoder packets, and N_MS denotes the number of modulation symbols allocated to a channel resource comprised of one slot and one subchannel.

15. The method of claim 12, wherein when packet data to be transmitted to a particular user does not occupy all subcarriers for one slot during its transmission, the MPR is calculated by

$\mathrm{MPR}=\frac{N_{\mathrm{EP}}}{\sum _{}^{}}$

k = 1 N slot ⁢

∑

j N SCH , k ⁢

∑

i = 1 N OS , kj ⁢

N SCH

where N_OS,k,j denotes the total number of OFDM symbols allocated to a k^th slot and a j^th subchannel, N_SCH,k denotes the number of subchannels allocated to a k^th slot, N_EP denotes the number of encoder packets, and N_slot denotes the number of slots.

17. The method of claim 12, wherein the modulation order is determined according to a predetermined value based on the calculated MPR.

19. The method of claim 12, wherein the code rate is calculated by

code rate (R)=MPR/MO

where MO denotes a modulation order.

16. A method for determining a modulation order of packet data to be transmitted through a plurality of subcarriers, the method comprising the steps of:

determining a number of OFDM symbols to be transmitted, the number of subchannels and a size of an encoder packet;

calculating a Modulation order Product code Rate (MPR) for packet data to be transmitted based on the number of OFDM symbols to be transmitted, the number of subchannels and the size of an encoder packet; and

determining a modulation order according to the calculated MPR, wherein the MPR is calculated by

$\begin{array}{c}\mathrm{MPR}=\left(\mathrm{EP}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{size}\right)/\left(\mathrm{payload}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{modulation}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{symbols}\right)\\ =\left(\mathrm{EP}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{size}\right)/\left(48\times <br><br>\left(\mathrm{the}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{number}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{of}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{subchannel}\right)\right)\end{array}$

18. A method for determining a modulation order of packet data to be transmitted through a plurality of subcarriers, the method comprising the steps of:

determining a number of OFDM symbols to be transmitted, the number of subchannels and a size of an encoder packet;

calculating a Modulation order Product code Rate (MPR) for packet data to be transmitted based on the number of OFDM symbols to be transmitted, the number of subchannels and the size of an encoder packet; and

determining a modulation order according to the calculated MPR, wherein QPSK(modulation order

     2) is used if 0<

MPR<

1.5.

20. A receiver comprising:

a control message processor for extracting information on the number of subchannels, subchannel index information and modulation order information from a control message , wherein the modulation order is determined in a transmitter by a MPR which is calculated by

$\begin{array}{c}\mathrm{MPR}=\left(\mathrm{EP}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{size}\right)/\left(\mathrm{payload}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{modulation}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{symbols}\right)\\ =\left(\mathrm{EP}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{size}\right)/\left(48\times <br><br>\left(\mathrm{the}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{number}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{of}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{subchannel}\right)\right)\end{array}$

; and

a demodulator for demodulating and decoding traffic data based on the information on the number of subchannels, subchannel index information and the modulation order information.

21. A reception method comprising:

a control message processing step of extracting information on the number of subchannels, subchannel index information and modulation order information from a control message , wherein the modulation order is determined in a transmitter by a MPR which is calculated by

$\begin{array}{c}\mathrm{MPR}=\left(\mathrm{EP}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{size}\right)/\left(\mathrm{payload}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{modulation}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{symbols}\right)\\ =\left(\mathrm{EP}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{size}\right)/\left(48\times <br><br>\left(\mathrm{the}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{number}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{of}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{subchannel}\right)\right)\end{array}$

; and

a traffic processing step of demodulating and decoding traffic data using the information on the number of subchannels, subchannel index information, and the modulation order information.