SYSTEM FOR TRANSMITTING INFORMATION DATA FROM A TRANSMITTER TO A RECEIVER OVER A NESTED BLOCK CHANNEL

• US 20090060012A1
• Filed: 08/12/2008
• Published: 03/05/2009
• Est. Priority Date: 09/02/2007
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: GRESSET, Nicolas, Ghassan, Kraidy
• Granted Patent: US 8,054,870 B2
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/026 Co-operative diversity, e.g. using fixed or mobile stations as relays
• CPC Class Codes: H04B 7/15592 Adapting at the relay station communication parameters for supporting cooperative relaying, i.e. transmission of the same data via direct - and relayed path cooperative diversity H04B7/024
• CPC Class Codes: H04L 1/004 by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 2001/0097 Relays
• CPC Class Codes: H04L 27/22 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/38 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters

Abstract

The present invention concerns a system for transmitting information data from a transmitter to a receiver over nested block channel, the transmitter (TRD) comprising an encoder (ENC) following an error correcting code structure, the receiver (RCV) comprising a decoder (DEC) defined according to the error correcting code structure, the nested block channel (NBCH) comprising a scaled BPSK binary modulator (BM), the amplitude of which may vary from one bit transmission to the other. Such system is characterized in that the coding rate (Rc) of the encoder (ENC) or the parameters (D,L) of the nested block channel (NBCH) are selected dependently one from each other to achieve a target diversity order of the system and to maximize the coding gain.

Claims

1. ) System for transmitting information data from a transmitter to a receiver over nested block channel, the transmitter (TRD) comprising an encoder (ENC) following an error correcting code structure, the receiver (RCV) comprising a decoder (DEC) defined according to the error correcting code structure, the nested block channel (NBCH) comprising a scaled BPSK binary modulator (BM), the amplitude of which may vary from one bit transmission to the other, characterized in that the coding rate (Rc) of the encoder (ENC) or the parameters (D,L) of the nested block channel (NBCH) are selected dependently one from each other to achieve a target diversity order of the system and to maximize the coding gain.

2. ) System according to claim 1, a mathematical model of the nested block channel (NBCH) consisting in a concatenation of blocks, said nested block channel having two parameters which are a set of diversity orders D={D(1), . . . , D(k), . . . , D(|D|)} and a set of lengths of blocks L={L(1), . . . , L(k), . . . , L(|D|)}, where |D| is the cardinality of the set of diversity orders D, the number of concatenated blocks being equals to |D|, the fading random variable associated to the i-th block being defined by a combination of a subset S(i) of D(i) random variables with the integer value D(i)≦

λ

where λ

is an integer number of independent fading distributions, such that S(i+1)⊂

S(i), which means ∀

i<

j, D(i)≧

D(j) and assuming that D(1)=λ

has the highest diversity order, characterised in that the coding rate (Rc) of the encoder (ENC), the two parameters (D, L) of the nested block channel (NBCH) and the achievable target diversity order δ

of the system are linked by the relationship

$\mathrm{\delta <br><br>}=D<br><br>\left(i\right)<br><br><br><br>\mathrm{where}<br><br><br><br>i<br><br><br><br>\mathrm{is}<br><br><br><br>\mathrm{given}<br><br><br><br>\mathrm{by}<br><br><br><br>\underset{k=1}{\overset{i-1}{\sum <br><br>}}<br><br>L<br><br>\left(k\right)<<br><br>\mathrm{Rc}<br><br>\underset{k=1}{\overset{<br><br>D<br><br>}{\sum <br><br>}}<br><br>L<br><br>\left(k\right)\le <br><br>\underset{k=1}{\overset{i}{\sum <br><br>}}<br><br>L<br><br>\left(k\right)$

3. ) System according to claim 2, the nested block channel (NBCH) comprising a binary modulator (MOD) the output of which are vectors of modulation symbols (zi), a partial linear combiner (LC), a Sliding Triangular channel (ST) comprising M time slots and a detector (DET), characterised in that the modulation symbols (zi) of a same vector (Z) of modulation symbols are combined together thanks to the linear combiner (LC) which provides an output vector (X) of M combined symbols (xi) associated to one transmission over the Sliding Triangular channel (ST).

4. ) System according to claim 3, characterised in the first combined symbols (x1) and last s−

1 combined symbols (x(M+2−

s), . . . , x(M)) of said vector (X) of M combined symbols (xi) are linear combinations of the first s modulation symbols (zl, . . . , zs) and each of the other combined symbols (xi) is equal to one of the last M-s modulation symbols (zi), s being the partial combining size of the linear combiner.

5. ) System according to claim 4, the equivalent nested block channel (NBCH) having parameters D={M,M−

1 . . . , s} and L={sN/M,N/M, . . . , N/M}, characterised in that the coding rate (Rc) of the encoder (ENC), the number M of time slots of the Sliding Triangular (ST) channel and the partial combining size s of the linear combiner (LC) and the achievable target diversity order a are selected dependently one from each other thanks to the following relationship;

δ

=min(s+└

(1−

Rc)M┘

, M)

6. ) System according to claim 5, characterised in that the partial combining size s of the linear combiner is chosen according to the target diversity order δ

, the rate Rc of the encoder (ENC) and the number M of time slots of the Sliding Triangular (ST) channel, thanks to the following relationship;

s=arg min{δ

=min(s′

+└

(1−

Rc)M┘

,M)}

7. ) System according to claim 3, the number M of time slots of the transmission protocol which define the Sliding Triangular channel (ST) is a multiple of the partial linear combining size s of the linear combiner, the linear combiner is characterised in that the first combined symbols (x1) and last s−

1 symbols (x(M+2−

s), . . . , x(M)) are linear combinations of the first s modulation symbols (zl, . . . , zs), the second combined symbol (x2) and last s−

1 non-already considered combined symbols (x(M+3−

2s), . . . , x(M+1−

s)) are linear combinations of the s following and non already considered modulation symbols (z(s+1), . . . , z(2s)), and so on.

8. ) System according to claim 7, the equivalent nested block channel (NBCH) having parameters D={M,M−

1 . . . , M+1−

M/s} and L={sN/M, . . . , sN/M}, characterised in that the coding rate (Rc) of the encoder (ENC), the number M of time slots of the Sliding Triangular (ST) channel and the partial combining size s of the linear combiner (LC) and the achievable target diversity order δ

are selected dependently one from each other thanks to the following relationship;

$\mathrm{\delta <br><br>}=\min \left(\frac{M<br><br>\left(s-1\right)}{s}+1+\lfloor <br><br>\frac{\left(1-\mathrm{Rc}\right)<br><br>M}{s}\rfloor <br><br>,M\right)$

9. ) System according to claim 8, characterised in that the partial combining size s of the linear combiner is chosen according to the target diversity order δ

, the rate Rc of the encoder (ENC) and the number M of time slots of the Sliding Triangular (ST) channel, thanks to the following relationship;

$s=\underset{s^{\mathrm{\prime <br><br>}}}{\arg <br><br><br><br><br><br>\min }<br><br>\left\{\mathrm{\delta <br><br>}=\min \left(\frac{M<br><br>\left(s^{\mathrm{\prime <br><br>}}-1\right)}{s^{\mathrm{\prime <br><br>}}}+1+\lfloor <br><br>\frac{\left(1-\mathrm{Rc}\right)<br><br>M}{s^{\mathrm{\prime <br><br>}}}\rfloor <br><br>,M\right)\right\}$

10. ) System according to one of claims 1 to 9, characterised in that the detector (DET) performs an exhaustive marginalization in order to get estimates of the coded data bits being version of the information bits encoded through the encoder (ENC) under the form of Log Likelihood Ratio.

11. ) System according to one of claims 3 to 10, characterised in that the Sliding Triangular channel (ST) is defined by a Slotted Amplify-and-Forward protocol using β

relays, one use of said Sliding Triangular channel (ST) including (δ

+1) time slots of the Slotted Amplify-and-Forward protocol and the size of the linear combining matrix M equals β

+1.

12. ) System according to one of claims 1 to 11, characterized in that the transmitter (TRD) comprises a bit interleaver (INT) and the receiver (RCV) comprises a de-interleaver (DINT), the bit interleaver (INT) being designed according to the error correcting code structure in order to ensure that the performance at the output of the associated decoder (DEC) exhibits the achievable target diversity order.

13. ) System according to claim 12, characterised in that the error correcting code is systematic and the bit interleaver (INT) places the systematic bits on the blocks of highest diversity order of the equivalent nested block channel.

14. ) Transmitter (TRD) of a system for transmitting information data to a receiver (RCV) over nested block channel, the transmitter (TRD) comprising an encoder (ENC) following an error correcting code structure, the receiver (RCV) comprising a decoder (DEC) defined according to the error correcting code structure, the nested block channel (NBCH) comprising a scaled BPSK binary modulator (BM), the amplitude of which may vary from one bit transmission to the other, characterized in that the coding rate (Rc) of the encoder (ENC) or the parameters (D,L) of the nested block channel (NBCH) are selected dependently one from each other to achieve a target diversity order of the system and to maximize the coding gain.

15. ) Transmitter according to claim 14, a mathematical model of the nested block channel (NBCH) consisting in a concatenation of blocks, said nested block channel having two parameters which are a set of diversity orders D={D(1), . . . , D(k), . . . , D(|D|)} and a set of lengths of blocks L=where |D| is the cardinality of the set of diversity orders D, the number of concatenated blocks being equals to |D| the fading random variable associated to the i-th block being defined by a combination of a subset S(i) of D(i) random variables with the integer value D(i)≦

λ

where λ

is an integer number of independent fading distributions, such that S(i+1)⊂

S(i), which means ∀

i<

j, D(i)≧

D(j) and assuming that D(1)=λ

has the highest diversity order, characterised in that the coding rate (Rc) of the encoder (ENC), the two parameters (D, L) of the nested block channel (NBCH) and the achievable target diversity order δ

of the system are linked by the relationship

$\mathrm{\delta <br><br>}=D<br><br>\left(i\right)<br><br><br><br>\mathrm{where}<br><br><br><br>i<br><br><br><br>\mathrm{is}<br><br><br><br>\mathrm{given}<br><br><br><br>\mathrm{by}<br><br><br><br>\underset{k=1}{\overset{i-1}{\sum <br><br>}}<br><br>L<br><br>\left(k\right)<<br><br>\mathrm{Rc}<br><br>\underset{k=1}{\overset{<br><br>D<br><br>}{\sum <br><br>}}<br><br>L<br><br>\left(k\right)\le <br><br>\underset{k=1}{\overset{i}{\sum <br><br>}}<br><br>L<br><br>\left(k\right)$

16. ) Transmitter according to claim 15, the nested block channel (NBCH) comprising a binary modulator (MOD) the output of which are vectors of modulation symbols (zi), a partial linear combiner (LC), a Sliding Triangular channel (ST) comprising M time slots and a detector (DET), characterised in that the modulation symbols (zi) of a same vector (Z) of modulation symbols are combined together thanks to the linear combiner (LC) which provides an output vector (X) of M combined symbols (xi) associated to one transmission over the Sliding Triangular channel (ST).

17. ) Transmitter according to claim 16, characterised in the first combined symbols (x1) and last s−

1 combined symbols (x(M+2−

s), . . . , x(M)) of said vector (X) of M combined symbols (xi) are linear combinations of the first s modulation symbols (zl, . . . , zs) and each of the other combined symbols (xi) is equal to one of the last M-s modulation symbols (zi), s being the partial combining size of the linear combiner.

18. ) Transmitter according to claim 17, the equivalent nested block channel (NBCH) having parameters D={M,M−

1 . . . , s} and L={sN/M,N/M, . . . , N/M}, characterised in that the coding rate (Rc) of the encoder (ENC), the number M of time slots of the Sliding Triangular (ST) channel and the partial combining size s of the linear combiner (LC) and the achievable target diversity order δ

are selected dependently one from each other thanks to the following relationship;

δ

=min(s+└

(1−

Rc)M┘

,M)

19. ) Transmitter according to claim 18, characterised in that the partial combining size s of the linear combiner is chosen according to the target diversity order A, the rate Rc of the encoder (ENC) and the number M of time slots of the Sliding Triangular (ST) channel, thanks to the following relationship:

s=arg min{δ

=min(s′

+└

(1−

Rc)M┘

,M)}

20. ) Transmitter according to claim 16, the number M of time slots of the transmission protocol which define the Sliding Triangular channel (ST) is a multiple of the partial linear combining size s of the linear combiner, the linear combiner is characterised in that the first combined symbols (x1) and last s−

1 symbols (x(M+2−

s), . . . , x(M)) are linear combinations of the first s modulation symbols (zl, . . . , zs), the second combined symbol (x2) and last s−

1 non-already considered combined symbols (x(M+3-2s), . . . , x(M+1−

s)) are linear combinations of the s following and non already considered modulation symbols (z(s+1), . . . , z(2s)), and so on.

21. ) Transmitter according to claim 20, the equivalent nested block channel (NBCH) having parameters D={M,M−

1 . . . , M+1−

M/s} and L={sN/M, . . . , sN/M}, characterised in that the coding rate (Rc) of the encoder (ENC), the number M of time slots of the Sliding Triangular (ST) channel and the partial combining size s of the linear combiner (LC) and the achievable target diversity order δ

are selected dependently one from each other thanks to the following relationship;

$\mathrm{\delta <br><br>}=\min \left(\frac{M<br><br>\left(s-1\right)}{s}+1+\lfloor <br><br>\frac{\left(1-\mathrm{Rc}\right)<br><br>M}{s}\rfloor <br><br>,M\right)$

22. ) Transmitter according to claim 21, characterised in that the partial combining size s of the linear combiner is chosen according to the target diversity order δ

, the rate Rc of the encoder (ENC) and the number M of time slots of the Sliding Triangular (ST) channel, thanks to the following relationship;

$s=\underset{s^{\mathrm{\prime <br><br>}}}{\arg <br><br><br><br><br><br>\min }<br><br>\left\{\mathrm{\delta <br><br>}=\min \left(\frac{M<br><br>\left(s^{\mathrm{\prime <br><br>}}-1\right)}{s^{\mathrm{\prime <br><br>}}}+1+\lfloor <br><br>\frac{\left(1-\mathrm{Rc}\right)<br><br>M}{s^{\mathrm{\prime <br><br>}}}\rfloor <br><br>,M\right)\right\}$

23. ) Transmitter according to one of claims 14 to 22, characterized in that the transmitter (TRD) comprises a bit interleaver (INT) and the receiver (RCV) comprises a de-interleaver (DINT), the bit interleaver (INT) being designed according to the error correcting code structure in order to ensure that the performance at the output of the associated decoder (DEC) exhibits the achievable target diversity order.

24. ) Transmitter according to claim 23, characterised in that the error correcting code is systematic and the bit interleaver (INT) places the systematic bits on the blocks of highest diversity order of the equivalent nested block channel.