CA2625111A1 - A soft demodulating method for 16qam in communication system - Google Patents

A soft demodulating method for 16qam in communication system Download PDF

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Publication number
CA2625111A1
CA2625111A1 CA002625111A CA2625111A CA2625111A1 CA 2625111 A1 CA2625111 A1 CA 2625111A1 CA 002625111 A CA002625111 A CA 002625111A CA 2625111 A CA2625111 A CA 2625111A CA 2625111 A1 CA2625111 A1 CA 2625111A1
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Canada
Prior art keywords
decision
decided
tends
less
16qam
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CA002625111A
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French (fr)
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CA2625111C (en
Inventor
Pingbao Lv
Jianwu Dou
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ZTE Corp
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Individual
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/32Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/38Demodulator circuits; Receiver circuits
    • H04L27/3845Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier
    • H04L27/3854Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier using a non - coherent carrier, including systems with baseband correction for phase or frequency offset
    • H04L27/3863Compensation for quadrature error in the received signal

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

A soft demodulating method for 16-ary QAM(quadrature amplitude modulation) in a communication system can obtain average power of each constellation in 16QAM
by estimating receiving power in traffic channels; And then said received intermediate frequency signal can be made carrier wave delamination, and in-phase symbol sequence information I and quadrature symbol sequence information Q can be obtained; Based on the constellation mapping relation between said input binary bits sequence and I, Q branch, different decision segment and corresponding error probability decision curve can be determined; and in different decision segment, decision can be made for obtained in-phase symbol sequence information and quadrature symbol sequence information by using corresponding decision curve, in order to obtain real value soft information sequence; Finally, resulting real value sequence should be input to decoder and made error correction decoding, reception bits sequence corresponding to transmission bits can be decoded. Present invention can combine fully the advantage of hard decision and soft decision, the algorithm is simple, and it is can be realized easily.

Claims (5)

1. A soft demodulation method of 16 Quadrature Amplitude Modulation (16QAM), performing soft decision demodulation for binary bit sequence processed at sending end with 16QAM to get corresponding real value soft information sequence , including the following steps of:

estimating receiving power of traffic channel according to pilot power and power deviation between the traffic channel and pilot channel to obtain an average power P ave of 16QAM constellation;

removing carrier from intermediate frequency signals received in order to obtain in-phase symbol sequence information I and quadrature symbol sequence information Q;
determining different decision segments and their corresponding error probability decision curves according to constellation mapping relationship between the binary bit sequence input during said 16QAM and I, Q branches, and based on this, judging said obtained in-phase symbol sequence information and quadrature symbol sequence information in the different decision segments by using the corresponding decision curves in order to obtain real value soft information sequence .
2. The method according to claim 1, further including:

inputting said obtained real value sequence into a decoder for error correction decoding to obtain a received bits sequence corresponding to sent bits.
3. The method according to claim 1, wherein said 16QAM is a 16QAM in a High Speed Downlink Packet Access system; said step of determining the different decision segments and their corresponding error probability decision curves according to the mapping relationship is:

when the in-phase symbol information I is positive, the corresponding ~ tends to be decided as 0, the greater the I is, the higher a probability of right decision for ~ is; when the I is negative, the corresponding ~ tends to be decided as 1, and the less the I is, the higher the probability of right decision for ~ is;

when the quadrature symbol information Q is positive, the corresponding ~
tends to be decided as 0, and the greater the Q is, the higher the probability of right decision for ~ is;
when the Q is negative, the corresponding ~ tends to be decided as 1, and the less the Q is, the higher the probability of right decision for ~ is;

when the in-phase symbol information I is greater than 0.9487 or less than -0.9487, the corresponding ~ tends to be decided as 1; when the I is greater than -0.3162 and less than 0.3162, the corresponding ~ tends to be decided as 0; When the I is greater than -0.9487 and less than -0.3162 or the I is greater than 0.3162 and less than 0.9487, whether the corresponding ~ tends to be decided as 0 or as 1 is decided by a value of the I, the more the I
tends to be 0, the higher the probability of correctness of ~ being decided as 0 is, and the more the I tends to be I or -1, the higher the probability of correctness of ~
being decided as 1 is;

when the quadrature symbol information Q is greater than 0.9487 or less than -0.9487, the corresponding ~ tends to be decided as 1; when Q is greater than -0.3162 and less than 0.3162, the corresponding ~ tends to be decided as 0; when Q is greater than -0.9487 and less than -0.3162 or Q is greater than 0.3162 and less than 0.9487, whether the corresponding ~
tends to be decided as 0 or as I is decided by the value of the Q, the more the Q tends to be 0, the higher the probability of correctness of ~ being decided as 0 is, and the more the Q tends to be 1 or -1, the higher the probability of correctness of ~ being decided as 1 is.
4. The method according to claim 1, wherein said 16QAM is a 16QAM in a High Speed Downlink Packet Access system; said step of deciding the different decision segments and their corresponding error probability decision curves according to the mapping relationship is:

whatever the value of the I is, the error probability decision curve of ~should meet the equation: ;
whatever the value of the Q is, the error probability decision curve of ~should meet the equation: .
when the I is greater than or equal to 0, the error probability decision curve of ~ should meet the equation:

when the I is less than 0, the error probability decision curve of ~ should meet the equation:

when the Q is greater than or equal to 0, the error probability decision curve of ~should meet the equation:

when the Q is less than 0, the error probability decision curve of ~should meet the equation:

5. The method according to claim 4, wherein said value of 0.7071 corresponds to an in-phase or quadrature component of Quadrature Phase Shift Keying base band modulation with average constellation power being 1.
CA2625111A 2005-10-18 2005-10-18 A soft demodulating method for 16qam in communication system Expired - Fee Related CA2625111C (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2005/001708 WO2007045122A1 (en) 2005-10-18 2005-10-18 A soft demodulating method for 16qam in communication system

Publications (2)

Publication Number Publication Date
CA2625111A1 true CA2625111A1 (en) 2007-04-26
CA2625111C CA2625111C (en) 2011-10-04

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Family Applications (1)

Application Number Title Priority Date Filing Date
CA2625111A Expired - Fee Related CA2625111C (en) 2005-10-18 2005-10-18 A soft demodulating method for 16qam in communication system

Country Status (3)

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CN (1) CN101176325B (en)
CA (1) CA2625111C (en)
WO (1) WO2007045122A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9172500B2 (en) 2012-04-17 2015-10-27 Huawei Technologies Co., Ltd. Signal demodulation method and device

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5145766B2 (en) * 2007-05-21 2013-02-20 株式会社Jvcケンウッド Soft decision device and soft decision method
RU2713206C1 (en) * 2019-03-29 2020-02-04 Акционерное Общество Научно- Производственный Концерн "Барл" Signal demodulation method and device
CN111953446B (en) * 2019-05-14 2023-05-16 中兴通讯股份有限公司 Soft information hard decision configuration method, device, equipment and readable storage medium
CN111131107B (en) * 2019-12-04 2022-03-11 重庆邮电大学 Self-adaptive soft demodulation method based on 5G downlink shared channel state

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6735247B2 (en) * 2001-03-30 2004-05-11 Qualcomm, Incorporated Method and apparatus in a communication system
KR100800885B1 (en) * 2001-08-13 2008-02-04 삼성전자주식회사 Demodulation apparatus and method for communication using multi level modulation
US7580480B2 (en) * 2003-06-23 2009-08-25 Hong-seok Seo Demodulation method using soft decision for quadrature amplitude modulation and apparatus thereof
CN100518163C (en) * 2005-04-01 2009-07-22 东南大学 Method for fast realization of soft-demodulation and soft-modulation in high-order quadrature amplitude modulation

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9172500B2 (en) 2012-04-17 2015-10-27 Huawei Technologies Co., Ltd. Signal demodulation method and device

Also Published As

Publication number Publication date
CN101176325A (en) 2008-05-07
CA2625111C (en) 2011-10-04
WO2007045122A1 (en) 2007-04-26
CN101176325B (en) 2011-02-02

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