CN107370707B

CN107370707B - Signal processing method and device

Info

Publication number: CN107370707B
Application number: CN201610318943.8A
Authority: CN
Inventors: 王艺; 黄磊; 史桢宇
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2016-05-13
Filing date: 2016-05-13
Publication date: 2020-06-16
Anticipated expiration: 2036-05-13
Also published as: CN107370707A; WO2017193834A1

Abstract

The invention provides a signal processing method, which comprises the following steps: carrying out QAM modulation on a bit block and outputting N/2 QAM symbols, wherein the bit block comprises a plurality of bits; performing conjugation processing on the N/2 QAM symbols, and outputting N/2 conjugation symbols; sequentially mapping the N/2 QAM symbols to sub-carriers from 1 st to N/2 nd, and sequentially mapping the N/2 conjugate symbols to sub-carriers from N/2+1 th to N th according to the mapping sequence opposite to the N/2 QAM symbols; wherein N is the number of subcarriers; because 2 sub-carriers occupied by QAM symbols and conjugate symbols have a symmetrical relationship, the reliability of wireless signal transmission is improved under the condition of I/Q imbalance.

Description

Signal processing method and device

Technical Field

The present invention relates to the field of wireless communication, and in particular, to a signal processing method and apparatus.

Background

OFDM (Orthogonal Frequency Division multiplexing) is a multiplexing technique that has been widely used in wireless communication systems, has been used in LTE (Long Term Evolution) communication systems and IEEE802.11 systems, and is also one of candidate waveforms for 5G mobile communication systems. The Modulation technique is a process of converting a binary baseband signal into a transmittable digital signal, and the Modulation techniques widely used in the OFDM system are QAM (Quadrature Amplitude Modulation), such as 4-order QAM, 16-order QAM, 64-order QAM, etc., where the 4-order QAM is QPSK (Quadrature phase shift keying) Modulation.

The modulated signal is processed by OFDM to form a baseband signal, the baseband signal is expressed as a complex number formed by an I path and a Q path, and then the complex number is input into a middle radio frequency unit, and I/Q imbalance is a phenomenon commonly existing in the radio frequency unit in a wireless communication system. The middle radio frequency unit respectively amplifies the baseband signals to the I path and the Q path and modulates the baseband signals to a carrier frequency f_cThe above. At high frequencies (f)_c>6GHz), because the carrier frequency point is high and the bandwidth is large, the middle radio frequency unit can not accurately correct the parameters of the two paths of I/Q. Therefore, the I/Q imbalance phenomenon follows the carrier frequency f_cThe rise of the interference is more and more serious, and the I/Q imbalance reaches a certain degree to cause the distortion of signals, generate interference and reduce the wireless transmission performance.

In a high-frequency communication system, how to ensure reliable transmission of an OFDM modulation signal under a wireless channel under the condition of I/Q imbalance is a current difficulty.

Disclosure of Invention

The invention provides a signal processing method and a signal processing device, which are used for improving the reliability of wireless transmission of signals.

In one aspect, the present invention provides a signal processing method, including:

carrying out QAM modulation on a bit block and outputting N/2 QAM symbols, wherein the bit block comprises a plurality of bits; performing conjugation processing on the N/2 QAM symbols, and outputting N/2 conjugation symbols; sequentially mapping the N/2 QAM symbols to sub-carriers from 1 st to N/2 nd, and sequentially mapping the N/2 conjugate symbols to sub-carriers from N/2+1 th to N th according to the mapping sequence opposite to the N/2 QAM symbols; where N is the number of subcarriers.

In combination with the above aspects, in one embodiment, the QAM modulation is of order Q, Q ═ 2^2qQ is a natural number; it is convenient to extend the method to general QAM modulation.

In combination with the above aspects, N is an integer multiple of 2, i.e., N/2 is a positive integer.

In addition, as another embodiment, the QAM symbols may be multiple, such as greater or less than N/2; for example: if the number of QAM symbols is less than N/2, the conjugate symbols are also less than N/2, and some subcarriers are null after mapping. The number of QAM symbols is generally less than or equal to N/2.

In combination with the above aspects, the method further comprises: dividing the binary bit information stream into bit blocks; the above schemes are described by taking one bit block as an example; in practical applications, if there are multiple bit blocks, each bit block performs the above operations.

In combination with the above aspects, the method further comprises: and carrying out OFDM processing on the mapped N symbols, and outputting a baseband signal containing I/Q two paths.

In combination with the above aspects, the N/2 QAM symbols are (d)₁,d₂,…,d_N/2) N/2 conjugate symbols are (d)_P(1),d_P(2),…,d_P(N/2)) Then, the specific mapping process may be:

will sign d_kMapping to the kth subcarrier;

will sign d_P(k)To the p (k) th subcarrier, p (k) N-k + 1;

wherein k is 1,2, …, N/2.

For example, assuming that there are 8 subcarriers, according to the above mapping method, d₁Mapping to the 1 st subcarrier, d₂Mapping to the 2 nd subcarrier, d₃Mapping to the 3 rd subcarrier, d₄Mapping to the 4 th subcarrier, d_P(1)Mapping to the 8 th subcarrier, d_P(2)Mapping to the 7 th subcarrier, d_P(3)Mapping to the 6 th subcarrier, d_P(4)To the 5 th subcarrier.

In the above example, if there are only 3 QAM symbols (d)₁，d₂，d₃) And the conjugate symbol (d)_P(1)，d_P(2)，d_P(3)) Then the 4 th, 5 th sub-carrier is null.

In another aspect, the present invention further provides a signal processing method, including:

carrying out QAM modulation on a bit block and outputting a plurality of QAM symbols, wherein the bit block comprises a plurality of bits; performing conjugation processing on the QAM symbols and outputting a plurality of conjugate symbols; respectively carrying out spread spectrum processing on the QAM symbols and the conjugate symbols, and outputting N/2 spread QAM symbols and N/2 spread conjugate symbols; sequentially mapping the N/2 spread QAM symbols to the 1 st to the N/2 nd subcarriers, and sequentially mapping the N/2 spread conjugate symbols to the N/2+1 th to the N-th subcarriers according to the mapping sequence opposite to the N/2 spread QAM symbols; where N is the number of subcarriers.

Wherein N is an integer multiple of 2, namely N/2 is a positive integer.

In addition, as an embodiment, the spread QAM symbols may be multiple, such as greater than or less than N/2, for example: if the number of spread QAM symbols is less than N/2, the number of conjugate symbols is also less than N/2, and some subcarriers are null after mapping.

With the above aspects in mind, in one embodiment, the QAM symbols are N/(2M) and the conjugate symbols are N/(2M); N/(2M) is a positive integer.

The spread spectrum processing is M times spread spectrum processing, and M is 2ⁿAnd n is a natural number.

The scheme is suitable for a more general signal processing method combining QAM and OFDM technologies and is suitable for the condition that the spreading factor is larger than 2.

In combination with the above aspects, the QAM modulation is of order Q, Q2^2qAnd q is a natural number.

In combination with the above aspects, the method further comprises: dividing the binary bit information stream into bit blocks; the above scheme takes one bit block as an example for illustration; in practical applications, if there are multiple bit blocks, each bit block performs the above operations.

In combination with the above aspects, the spread N/2 QAM symbols are (d'₁,d’₂,…,d’_N/2) N/2 conjugate symbols after spreading are (d'_P(1),d’_P(1)+1,…,d’_P(1)+M-1,…,d’_P(N/2M),d’_P(N/2M)+1,…,d’_P(N/2M)+M-1(ii) a ) Then, the specific mapping process may be:

symbol d'_kMapping to the kth subcarrier, wherein k is 1,2, …, N/2;

symbol d'_P(k)+mMapping to the p (k) + M subcarriers, where k ═ 1,2, …, N/2M; m is 0,1, … M-1; p (k) ═ N-Mk + 1; mk means M × k.

For example, assuming that there are 8 subcarriers, according to the above mapping method, d₁Mapping to the 1 st subcarrier, d₂Mapping to the 2 nd subcarrier, d₃Mapping to the 3 rd subcarrier, d₄Mapping to the 4 th subcarrier, d_P(1)Mapping to the 8 th subcarrier, d_P(2)Mapping to the 7 th subcarrier, d_P(3)Mapping to the 6 th subcarrier, d_P(4)Mapping toThe 5 th subcarrier.

The above methods may be executed by a network device or a terminal.

In another aspect, the present invention further provides a signal processing apparatus, including:

the modulation module is used for carrying out QAM modulation on a bit block and outputting N/2 QAM symbols, wherein the bit block comprises a plurality of bits; a conjugation module, configured to perform conjugation processing on the N/2 QAM symbols, and output N/2 conjugate symbols; a mapping module, configured to map the N/2 QAM symbols to the 1 st to N/2 nd subcarriers in sequence, and map the N/2 conjugate symbols to the N/2+1 th to N th subcarriers in sequence according to a mapping order opposite to the N/2 QAM symbols; where N is the number of subcarriers.

In combination with the above aspects, wherein the QAM modulation is of order Q, Q2^2qAnd q is a natural number.

With reference to the above aspect, the apparatus may further include a segmentation module configured to divide the binary bit information stream into bit blocks, and input the bit blocks into the modulation module; the generated bit block is usually plural.

The device may further include an OFDM module configured to perform OFDM processing on the N mapped symbols output by the mapping module, and output a baseband signal including two I/Q paths.

In another aspect, the present invention also provides a signal processing apparatus, including:

the modulation module is used for carrying out QAM modulation on a bit block and outputting a plurality of QAM symbols, wherein the bit block comprises a plurality of bits; a conjugation module, configured to perform conjugation processing on the multiple QAM symbols, and output multiple conjugate symbols; the spread spectrum module is used for respectively carrying out spread spectrum processing on the QAM symbols and the conjugate symbols and outputting N/2 spread spectrum QAM symbols and N/2 spread spectrum conjugate symbols; a mapping module, configured to sequentially map the N/2 spread QAM symbols to sub-carriers 1 to N/2, and sequentially map the N/2 spread conjugate symbols to sub-carriers N/2+1 to N according to a mapping order opposite to the N/2 spread QAM symbols; where N is the number of subcarriers.

With reference to the above aspect, the QAM symbols are N/(2M), and the conjugate symbols are N/(2M); the spread spectrum processing is M times spread spectrum processing, and M is 2ⁿAnd n is a natural number.

In combination with the above aspect, wherein the QAM modulation is of order Q, Q ═ 2^2qAnd q is a natural number.

The signal processing method and the device sequentially map a plurality of QAM symbols after spread spectrum processing to the 1 st to the N/2 nd subcarriers in sequence, and sequentially map a plurality of conjugate symbols after spread spectrum processing to the N/2+1 st to the N th subcarriers according to the mapping sequence opposite to the plurality of QAM symbols, because the QAM symbols and the 2 subcarriers occupied by the conjugate symbols have a symmetrical relation, the reliability of wireless signal transmission is improved under the condition of I/Q imbalance.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

FIG. 1A is a system block diagram of a SQPSK-OFDM signal processing method in an IEEE802.11ad system.

Fig. 1B is a system block diagram of a signal processing method according to an embodiment of the invention.

Fig. 2 is a diagram illustrating QAM symbols and conjugate symbols after mapping to subcarriers.

Fig. 3 is a system block diagram of a signal processing method according to another embodiment of the present invention.

Fig. 4 is a schematic diagram of a signal processing apparatus according to an embodiment of the present invention.

Fig. 5 is a schematic diagram of a signal processing apparatus according to another embodiment of the invention.

Fig. 6 is a schematic diagram of a signal processing apparatus according to another embodiment of the invention.

Detailed Description

The embodiment of the invention can be used for various wireless networks based on OFDM technology. The radio access network may comprise different network elements in different systems. For example, network elements of a radio Access network in LTE (long Term evolution) and LTE-a (LTE advanced) include an eNB (eNodeB), and network elements of wlan (wireless local area network)/Wi-Fi include an Access Point (AP). Other wireless networks may also use similar schemes as the embodiments of the present invention, except that the relevant modules in the base station system may be different, and the embodiments of the present invention are not limited.

It should also be understood that, in the embodiment of the present invention, the User Equipment (UE) includes, but is not limited to, a Mobile Station (MS), a Mobile Terminal (Mobile Terminal), a Mobile phone (Mobile Telephone), a handset (handset), a portable device (portable Equipment), and the like, and the User Equipment may communicate with one or more core networks via a Radio Access Network (RAN), for example, the User Equipment may be a Mobile phone (or referred to as a "cellular" phone), a computer with a wireless communication function, and the User Equipment may also be a portable, pocket, handheld, built-in computer, or vehicle-mounted Mobile device.

SQAM (spread Quadrature Amplitude Modulation) is a Modulation method combining QAM Modulation technology and spread spectrum, and the Modulation method mainly used in the wireless communication system at present is SQPSK (spread Quadrature Phase Shift Keying), that is, a Modulation method combining 4-order QAM (QPSK Modulation) and spread spectrum technology. Specifically, the same QPSK symbol S is transmitted twice, which is respectively the conjugate conj (S) of S and S, and is equivalent to spreading by 2 times. Because the sent symbols S and conj (S) occupy two time-frequency units and are transmitted in different subcarriers, the diversity gain of two time-frequency resources can be obtained in a wireless channel, and the reliability of signal transmission is ensured.

In a wireless communication system based on the OFDM technology, for example, ieee802.11ad, SQPSK is one of basic modulation schemes, fig. 1A shows a schematic diagram of a signal processing system combining the SQPSK and the OFDM technology, and the signal processing method will be described below with reference to the schematic diagram.

101 stream of binary bits c_kThe binary bit stream c enters a segmentation module which segments the binary bit stream c_kThe stream is divided into blocks of bits, each block having N bits, denoted (c)₁,c₂,…,c_N) Wherein N is the number of subcarriers, and may be all subcarriers or part of subcarriers used for data transmission in the OFDM system; each block of bits is input to a QPSK modulation block.

102, after each bit block is input into the QPSK modulation module, taking a bit block as an example, the QPSK modulation module performs QPSK modulation on the bit block, and outputs a plurality of QPSK symbols to the mapping module and the conjugation module.

Taking a bit block as an example, every two bits are taken as a pair of bits, and each pair of bits (c) is taken by the QPSK modulation module_2k-1,c_2k) Wherein k is 1,2, …, N/2, mapping to a QPSK constellation point in the QPSK constellation diagram, and outputting N/2 QPSK symbols (d) after mapping₁,d₂,…,d_N/2) To a mapping module and a conjugation module.

103, the conjugation module pairs the input N/2 QPSK symbols (d)₁,d₂,…,d_N/2) Performing conjugation to generate conjugate symbol d_P(k)Specifically, it may be d_P(k)＝conj(d_k) Outputting N/2 QPSK conjugate symbols (d)_P(1),d_P(2),…,d_P(N/2)) To the mapping module.

Thus, one isSymbol d_kIs transmitted twice, respectively d_kAnd d_P(k)Equivalent to 2 times of spread spectrum, and the spreading sequence is equivalent to [ +1, +1 [)]。

The N/2 QPSK symbols (d) in the above step 102₁,d₂,…,d_N/2) And N/2 QPSK conjugate symbols (d) in step 103_P(1),d_P(2),…,d_P(N/2)) Are input to the mapping module.

104, a mapping module maps the N/2 QPSK symbols (d)₁,d₂,…,d_N/2) And said N/2 QPSK conjugate symbols (d)_P(1),d_P(2),…,d_P(N/2)) And N symbols are mapped to the N subcarriers in sequence.

The specific method is to use QPSK symbol d_kMapping to the kth subcarrier, wherein k is 1,2, …, N/2; conjugating the QPSK with a symbol d_P(k)Mapping to the p (k) ═ k + N/2 subcarriers, where k is 1,2, …, N/2; thus, d_kOccupying half of the OFDM sub-carriers, d_P(k)Occupying the other half of the OFDM subcarriers. The mapped N symbols are then input to the OFDM module.

And 105, the OFDM module carries out OFDM processing on the mapped N symbols and outputs baseband signals containing I/Q channels. The OFDM processing is prior art and will not be described in detail.

The above described SQPSK-OFDM signal processing procedure has been applied in ieee802.11ad.

In an embodiment of the present invention, the signal processing method is improved, and in particular, the mapping method of step 104 is improved, and QPSK symbol d is used_kThe mapping method of step 104 is still adopted, and the first N/2 sub-carriers are mapped in sequence, but the QPSK conjugate symbol d_P(k)According to the QPSK symbol d_kThe reverse order maps to the last N/2 sub-carriers; referring to fig. 1B, the method specifically includes:

201 to 203, synchronous steps 101 to 103; and will not be described in detail.

204 mapping module maps N/2 QPSK symbols (d)₁,d₂,…,d_N/2) Sequentially mapping the data to the 1 st to the N/2 th sub-carriers of the OFDM; co-QPSKYoke symbol (d)_P(1),d_P(2),…,d_P(N/2)) Mapping to N/2+1 to N sub-carriers of OFDM in sequence in reverse order of QPSK symbol, and inputting the mapped N symbols to OFDM module.

The specific mapping method comprises the following steps: QPSK symbol d_kMapping to k-th subcarrier, wherein k is 1,2, …, N/2, and occupies half of OFDM subcarrier; conjugating the QPSK with a symbol d_P(k)And mapping to the p (k) -N-k +1 sub-carriers, wherein k is 1,2, …, N/2, and occupies the other half of OFDM sub-carriers.

205, a synchronization step 105; and will not be described in detail.

Fig. 2 shows schematic diagrams of different mapping results obtained by the two different mapping methods, where when the number of subcarriers is 8, that is, N is 8, the numbers of the subcarriers are sequentially 1 to 8, the left side of the diagram is the mapping result obtained after step 104 is adopted, and the right side of the diagram is the mapping result obtained after step 204 is adopted. That is, the 1 st to 4 th QAM symbols are mapped to the 1 st to 4 th sub-carriers in sequence, and the 1 st to 4 th QAM conjugate symbols are mapped to the 5 th to 8 th sub-carriers in sequence according to the reverse mapping sequence of the QAM symbols.

The above method embodiment is described by taking 4-order QAM modulation (i.e. QPSK modulation) as an example, and those skilled in the art can know that 16-order QAM, 64-order QAM, and the like can be applied to the above method, and only the QPSK modulation module in fig. 1 needs to be replaced by a Q-QAM module, where Q represents a QAM order; QAM module outputs N/2 QAM symbols (d)₁,d₂,…,d_N/2) To a mapping module and a conjugation module, the conjugation module outputs N/2 QAM conjugated symbols (d)_P(1),d_P(2),…,d_P(N/2)) To the mapping module, the other steps are consistent with the above embodiments.

The above embodiments can be summarized as follows:

carrying out QAM modulation on a bit block and outputting a plurality of QAM symbols, wherein the bit block comprises a plurality of bits; performing conjugation processing on the QAM symbols and outputting a plurality of conjugate symbols; mapping the QAM symbols to sub-carriers from 1 st to N/2 th in sequence, and mapping the conjugate symbols to sub-carriers from N/2+1 th to N + 2 th in sequence according to the mapping sequence opposite to the N/2 QAM symbols; where N is the number of subcarriers.

In general, the number of QAM symbols is less than or equal to N/2, and the number of QAM conjugate symbols is less than or equal to N/2. The total number of QAM symbols and conjugate symbols is less than or equal to the number of subcarriers N.

In addition, from the perspective of the mapping module in fig. 1B, an embodiment of the present invention further discloses a mapping method, including:

receiving a plurality of QAM symbols and a plurality of QAM conjugate symbols;

sequentially mapping the N/2 QAM symbols to sub-carriers from 1 st to N/2 nd, and sequentially mapping the N/2 conjugate symbols to sub-carriers from N/2+1 th to N th according to the mapping sequence opposite to the N/2 QAM symbols; where N is the number of subcarriers. The specific mapping method is consistent with the above embodiments.

The above method is written from the perspective of the mapping module, without regard to the processing before the QAM symbols and the QAM conjugate symbols.

The spreading of the above embodiment is limited to the case where the spreading factor is 2, and a more general spreading scheme is not given, such as the case where the spreading factor is greater than 2.

Fig. 3 shows a schematic diagram of a signal processing system combining QAM and OFDM techniques, and the signal processing method is described below with reference to the schematic diagram.

Consider the general case of Q-QAM modulation, Q being the QAM order, Q being 2^2qQ is a natural number, such as 1,2,3, 4, etc.; the spreading factor is 2M, wherein M is a natural number smaller than N/2, N/2M is an even number, N is the number of subcarriers, and can be all subcarriers or part of subcarriers used for data transmission in the OFDM system. Referring to fig. 3, the process flow of the method is as follows:

301, stream of binary bits c_kThe binary bit stream c enters a segmentation module which segments the binary bit stream c_kDividing the stream into a plurality of bit blocks, and inputting each bit block into a Q-QAM module;

specifically, each block may have Nq/M bits, denoted as (c)₁,c₂,…,c_Nq/M) Nq/M means (Nxq)/M. Each bit block is then input to a Q-QAM block for modulation.

And 302, after each bit block is input into a Q-QAM module, taking one bit block as an example, the Q-QAM module performs Q-order QAM modulation on the bit block and outputs a plurality of QAM symbols to a spreading module and a conjugate module.

Taking a bit block as an example, the Q-QAM module will count every 2Q bits (c)_2q(k-1)+1,…c_2qk) Mapping into a Q-QAM constellation point in a Q-QAM constellation diagram; then outputs N/2M Q-QAM symbols (d)₁,d₂,…,d_N/2M) To the spreading and conjugation modules, where k is 1,2, …, N/2M meaning N/(2 × M).

303, the conjugation module performs conjugation on the input N/2M Q-QAM symbols to generate a conjugated symbol d_P(k)Is recorded as d_P(k)＝conj(d_k) Outputting N/2M Q-QAM conjugate symbols (d)_P(1),d_P(2),…,d_P(N/2M)) To the spreading module.

Therefore, two paths of symbols are input into the spread spectrum module, and one path is N/2M QAM symbols (d) output by the Q-QAM module₁,d₂,…,d_N/2M) The other path is N/2M QAM conjugate symbols (d) output by the conjugate module_P(1),d_P(2),…,d_P(N/2M))。

304, the input of the spreading module is composed of N/2M QAM symbols (d)₁,d₂,…,d_N/2M) And N/2M QAM conjugated symbols (d)_P(1),d_P(2),…,d_P(N/2M)) Composed of N/M symbols, spread spectrum unit for inputting symbols d_kAnd d_P(k)And performing M-time spread spectrum.

The specific spreading method may be:

d’_(k-1)M+1＝d_k×s₁,d’_(k-1)M+2＝d_k×s₂,…,d’_kM＝d_k×s_M；k＝1,2,…,N/2M；

d’_P(k)＝d_P(k)×s_M+1,d’_P(k)+1＝d_P(k)×s_M+2…,d’_P(k)+M-1＝d_P(k)×s_2M；k＝1,2,…,N/2M；

wherein { s_mAnd M is a spreading sequence with the length of 2M, namely 1,2, … and 2M.

The spreading module outputs N spread symbols to the mapping module, and specifically includes N/2 spread QAM symbols (d'₁,d’₂,…,d’_N/2) And N/2 spread QAM conjugate symbols (d'_P(1),d’_P(1)+1,…,d’_P(1)+M-1,…,d’_P(N/2M),d’_P(N/2M)+1,…,d’_P(N/2M)+M-1；)。

305, a mapping module maps the spread N symbols to N subcarriers of OFDM, wherein N/2 spread QAM symbols (d'₁,d’₂,…,d’_N/2) Sequentially mapping the symbols to the 1 st to the N/2 th subcarriers in sequence, and enabling N/2 spread QAM conjugated symbols (d'_P(1),d’_P(1)+1,…,d’_P(1)+M-1,…,d’_P(N/2M),d’_P(N/2M)+1,…,d’_P(N/2M)+M-1(ii) a ) Sequentially mapping to the N/2+1 to the Nth subcarriers according to the reverse order of the QAM symbols, namely N/2 spread QAM conjugate symbols (d'_P(1),d’_P(1)+1,…,d’_P(1)+M-1,…,d’_P(N/2M),d’_P(N/2M)+1,…,d’_P(N/2M)+M-1(ii) a ) And sequentially mapping to the Nth to the (N/2 + 1) th subcarriers according to the sequence.

The concrete method is that the symbol d'_kMapping to the kth subcarrier, wherein k is 1,2, …, N/2;

symbol d'_P(k)+mMapping to the p (k) + M subcarriers, where k ═ 1,2, …, N/2M; m is 0,1, … M-1; wherein p (k) is N-M × k + 1.

The mapped N symbols are then input to the OFDM module.

Assuming that N is 8, the mapped schematic diagram can also refer to fig. 2.

And 306, the OFDM module carries out OFDM processing on the mapped N symbols and outputs baseband signals containing I/Q paths. The OFDM module processing is prior art and will not be described in detail.

This embodiment has one more spreading step compared to the previous embodiment, where the spreading factor is 2M, and M is 2ⁿN is more than or equal to 0, QAM modulation is not limited to 4 orders and can be 16-order QAM, 64-order QAM, 256-order QAM and the like. When QAM modulation is of order 4 and the spreading factor is 2, that is, when n is 0 and M is 1, each symbol is spread by 1 time, which is equivalent to the embodiment described in fig. 1B, and if n is a natural number, such as 1,2,3, etc., the case where the spreading factor described in the embodiment of fig. 1B is 2 is excluded. The embodiment realizes a more universal SQAM modulation signal processing process based on the OFDM system.

The above embodiments can be summarized as follows:

carrying out QAM modulation on a bit block and outputting a plurality of QAM symbols, wherein the bit block comprises a plurality of bits; performing conjugation processing on the QAM symbols and outputting a plurality of conjugate symbols; respectively performing spread spectrum processing on the QAM symbols and the conjugate symbols, and outputting a plurality of spread QAM symbols and a plurality of spread conjugate symbols; mapping the spread QAM symbols to sub-carriers from 1 st to N/2 th in sequence, and mapping the spread conjugate symbols to sub-carriers from N/2+1 th to N in sequence according to the mapping sequence opposite to the spread QAM symbols; where N is the number of subcarriers.

Under normal conditions, the number of spread QAM symbols is less than or equal to N/2, and the number of spread QAM conjugate symbols is also less than or equal to N/2; the total number of spread QAM symbols and spread conjugate symbols is less than or equal to the number of subcarriers N.

In addition, from the perspective of the mapping module in fig. 3, an embodiment of the present invention further discloses a mapping method, including:

receiving a plurality of spread QAM symbols and a plurality of spread QAM conjugate symbols;

mapping the spread QAM symbols to sub-carriers from 1 st to N/2 th in sequence, and mapping the spread QAM conjugate symbols to sub-carriers from N/2+1 th to N in sequence according to the mapping sequence opposite to the QAM symbols; where N is the number of subcarriers. The specific mapping method is consistent with the above embodiments.

In the above embodiment, the spread QAM symbols are less than or equal to N/2, and the number of spread QAM conjugate symbols is also less than or equal to N/2; the total number of spread QAM symbols and spread conjugate symbols is less than or equal to the number of subcarriers N.

It should be noted that, each embodiment of the present invention is described by taking QAM modulation as an example, which is the most commonly used modulation method at present, and if there are other modulation methods to produce other modulation symbols, the signal processing method and the mapping method of the present invention can also be used, and are not described in detail.

In the method of the embodiment of the present invention, because the QAM conjugate symbols are mapped to the subcarriers in the order opposite to the QAM symbols, and after the receiving side performs OFDM demodulation, the distortion signal generated by partial I/Q imbalance is changed from interference to an effective signal by using the relationship between two symmetric subcarriers, the reliability of wireless transmission of the signal is improved under the condition of I/Q imbalance, and the receiving performance is further improved.

Based on the SQAM-OFDM signal processing method, the sending end executes the method, and before sending data, the sending end can send the following configuration information to the receiving end, such as:

modulation order, which can be included in mcs (modulation and coding scheme) information;

if a plurality of spread spectrum factors exist, the transmitting end needs to transmit the adopted spread spectrum factor 2M to the receiving end; if the system only adopts one spread spectrum, the transmitting end does not need to transmit the spread spectrum factor to the receiving end;

if a plurality of spread spectrum sequences exist, the transmitting end needs to transmit the currently adopted spread spectrum serial number to the receiving end;

based on the SQAM-OFDM scheme of the invention, the configuration information from the sending end to the receiving end can be sent to the receiving end in advance through a control channel, a broadcast channel or a data channel. After receiving the configuration information, the receiving end demodulates the SQAM-OFDM based on the configuration information.

The SQAM-OFDM signal processing scheme of the embodiment of the invention can be applied to a multi-carrier communication system. Such as: ieee802.11ay has determined that higher rates of data are transmitted using multiple carriers, each of which has a bandwidth of 2.16 GHz. The method can also be applied to the future 5G communication system, and the joint transmission of a plurality of carriers is divided into two cases.

Continuous multiple carriers: a plurality of carriers are contiguous over a frequency spectrum; in this case, N in the embodiment shown in fig. 1 or 3 is replaced with N ═ N_cN, wherein N_cThe number of carriers is 2 or 4, etc.; n is the number of subcarriers per carrier, and the other steps are unchanged.

Discrete multi-carrier: the multiple carriers are not contiguous in the frequency spectrum. In this case, each carrier is OFDM-modulated and demodulated. The SQAM-OFDM signal processing scheme in the above embodiments is applied to the discrete multi-carrier case, i.e., different carriers transmit different data. Suppose there is N_cA bit stream to be modulated for each carrier is

The SQAM-OFDM signal processing is performed for each carrier according to the steps of the embodiment shown in fig. 1 or fig. 3, respectively, as the transmission signal of the nth carrier.

The SQAM-OFDM signal processing scheme of the present invention can also be applied to SU-MIMO (single user multiple-input multiple-output) cases. Such as: IEEE802.11ay can configure SU-MIMO allowed transmission N_sA separate data stream, wherein

N

_s2, 4. The following are totally distinguished:

single carrier SU-MIMO transmission: the SQAM-OFDM of the present invention is applied to the SU-MIMO case of a single carrier, e.g., a base station prepares N for a certain user equipment_sA single independent data bit stream

Each bit stream performs corresponding steps according to the embodiment shown in fig. 1 or fig. 3, and performs SQAM-OFDM signal processing as a transmission signal of the nth antenna.

SU-MIMO transmission of multiple consecutive carriers: the SQAM-OFDM of the present invention is applied to SU-MIMO case of multiple continuous carriers, and firstly N is prepared for a certain user equipment_sEach independent length is N ═ N_cN data bit stream

Wherein N is_cThe number of carriers, and each data bit stream is processed according to the steps of the embodiment shown in fig. 1 or fig. 3, wherein N is replaced by N', and the output of SQPSK-OFDM modulation is used as the transmission signal of the nth antenna.

SU-MIMO transmission of multiple discrete carriers: the SQAM-OFDM of the present invention is applied to SU-MIMO case of multiple continuous carriers, and firstly N is prepared for a certain user_c*N_sIndependent data bit stream with length N

Wherein N is_cIs the number of carriers, Ns is the number of antennas; each data bit stream is processed according to the steps of the embodiment of figure 1 or figure 3 to obtain SQAM-OFDM signal, and the output of SQAM-OFDM modulation is used as the nth_sRoot antenna and n_cA transmission signal of each carrier.

The SQAM-OFDM scheme of the invention is applied to the conditions of multi-carrier and SU-MIMO, and a sending end needs to send the following configuration information to a receiving end before sending data:

the number of multiple carriers, for example, two bits, indicates 1/2/3/4 carriers;

whether the multiple carriers are discrete or continuous, e.g., one bit for discrete or continuous;

the number of data streams for SU-MIMO transmission, e.g., 1/2/4 data streams represented by two bits;

Further extension and generalization, the scheme can also be applied to MU-MIMO (multi-user multiple-input multiple-output).

The above embodiments of the method may be executed by a device on a network side, such as a base station, an access point, etc., or may be executed by a terminal, such as a mobile phone, a notebook computer, a vehicle-mounted mobile device, etc., and the method corresponding to the embodiment in fig. 1B is executed mainly, and the present invention further provides a signal processing apparatus in an OFDM system, and with reference to fig. 4, the apparatus includes:

a modulation module 401, configured to perform QAM modulation on a bit block, and output N/2 QAM symbols to a conjugation module 402 and a mapping module 403, where the bit block includes multiple bits;

a conjugation module 402, configured to perform conjugation on the N/2 QAM symbols, and output the N/2 conjugate symbols to a mapping module 403;

a mapping module 403, configured to sequentially map the N/2 QAM symbols to sub-carriers 1 to N/2, and sequentially map the N/2 conjugate symbols to sub-carriers N/2+1 to N according to a mapping order opposite to the N/2 QAM symbols; where N is the number of subcarriers.

In combination with the above aspect, wherein the QAM modulation is QPSK modulation.

Further, the apparatus may further include a segmentation module 400 configured to divide the binary bit information stream into bit blocks, and input the bit blocks to the modulation module 401; the generated bit block is usually plural.

The apparatus may further include an OFDM module (not shown in the figure), configured to perform OFDM processing on the mapped N symbols output by the mapping module 403, and output a baseband signal including two I/Q paths. The OFDM processing is prior art and will not be described in detail.

The above-mentioned apparatus may correspond to the execution main body of the method embodiment of step fig. 1B, and the corresponding modules respectively execute the corresponding method steps, which are not described in detail.

In another aspect, the method corresponding to the embodiment of fig. 3 is executed, and the present invention further provides a signal processing apparatus in an OFDM system, and with reference to fig. 5, the method includes:

a modulation module 501, configured to perform QAM modulation on a bit block, and output a plurality of QAM symbols to a conjugation module 502 and a spreading module 503, where the bit block includes a plurality of bits;

a conjugation module 502, configured to perform conjugation processing on the multiple QAM symbols, and output multiple conjugate symbols to a spreading module 503;

a spreading module 503, configured to perform spreading processing on the multiple QAM symbols and the multiple conjugate symbols, and output N/2 spread QAM symbols and N/2 spread conjugate symbols;

a mapping module 504, configured to sequentially map the N/2 spread QAM symbols to sub-carriers 1 to N/2, and sequentially map the N/2 spread conjugate symbols to sub-carriers N/2+1 to N according to a mapping order opposite to the N/2 spread QAM symbols; where N is the number of subcarriers.

Further, the apparatus may further include a segmentation module 500 configured to divide the binary bit information stream into bit blocks, and input the bit blocks into the modulation module 501; the generated bit block is usually plural.

The apparatus may further include an OFDM module (not shown in the figure) for performing OFDM processing on the mapped N symbols output by the mapping module 504, and outputting a baseband signal including two I/Q paths. The OFDM processing is prior art and will not be described in detail.

The above-mentioned apparatus may correspond to the execution main body of the method embodiment of fig. 3, and the corresponding modules respectively execute the corresponding method steps, which are not described in detail.

Still another embodiment of the two above-mentioned embodiments of the apparatus, referring to fig. 6, includes a processor, a transceiver, and a memory, where the transceiver is configured to perform transceiving processing on a signal, and the processor is configured to perform various processing procedures, such as: the functions of one or more of the modulation module 401, the conjugation module 402, the mapping module 403, the segmentation module 400 and the OFDM module in the apparatus shown in fig. 4 may be implemented; the functions of one or more of the modulation module 501, the conjugation module 502, the spreading module 503, the mapping module 504, the segmentation module 500 and the OFDM module in the apparatus shown in fig. 5 may also be implemented.

Optionally, the various components of the device in FIG. 6 are coupled together by a bus system that includes a power bus, a control bus, and a status signal bus in addition to a data bus.

The device shown in fig. 6 can implement each process implemented in the embodiments of the foregoing methods, and is not described here again to avoid repetition.

In addition, in the corresponding method embodiment, only the situation of the mapping module is considered, and the embodiment of the present invention further discloses a signal processing apparatus, including:

a receiving unit: receiving N/2 QAM symbols and N/2 QAM conjugate symbols;

a mapping unit: sequentially mapping the N/2 QAM symbols to sub-carriers from 1 st to N/2 nd, and sequentially mapping the N/2 conjugate symbols to sub-carriers from N/2+1 th to N th according to the mapping sequence opposite to the N/2 QAM symbols; where N is the number of subcarriers.

Or

A receiving unit: for receiving N/2 QAM symbols and N/2 QAM conjugate symbols;

The specific mapping method has been described in detail in the above method embodiments.

For another form of embodiment, the receiving unit may be implemented by a receiver, and the mapping unit may be implemented by a processor.

It should be understood that, in the embodiments of the present invention, the processor may be a Central Processing Unit (CPU), and the processor may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory may include both read-only memory and random access memory, and provides instructions and data to the processor. The portion of memory may also include non-volatile random access memory. For example, the memory may also store device type information.

The bus system may include a power bus, a control bus, a status signal bus, and the like, in addition to the data bus. For clarity of illustration, however, the various buses are labeled as a bus system in the figures.

It should be understood that the term "and/or" herein is merely one type of association relationship that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

It should be understood that, in various embodiments of the present invention, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A signal processing method, comprising:

carrying out QAM modulation on a bit block and outputting N/2 QAM symbols, wherein the bit block comprises a plurality of bits;

performing conjugation processing on the N/2 QAM symbols, and outputting N/2 conjugation symbols;

sequentially mapping the N/2 QAM symbols to sub-carriers from 1 st to N/2 nd, and sequentially mapping the N/2 conjugate symbols to sub-carriers from N/2+1 th to N th according to the mapping sequence opposite to the N/2 QAM symbols;

where N is the number of subcarriers.

2. The method of claim 1, wherein the QAM modulation is of order Q, Q-2^2qAnd q is a natural number.

3. A signal processing method, comprising:

carrying out QAM modulation on a bit block and outputting a plurality of QAM symbols, wherein the bit block comprises a plurality of bits;

performing conjugation processing on the QAM symbols and outputting a plurality of conjugate symbols;

respectively carrying out spread spectrum processing on the QAM symbols and the conjugate symbols, and outputting N/2 spread QAM symbols and N/2 spread conjugate symbols;

sequentially mapping the N/2 spread QAM symbols to the 1 st to the N/2 nd subcarriers, and sequentially mapping the N/2 spread conjugate symbols to the N/2+1 th to the N-th subcarriers according to the mapping sequence opposite to the N/2 spread QAM symbols;

where N is the number of subcarriers.

4. The method of claim 3, wherein:

the QAM symbols are N/(2M), and the conjugate symbols are N/(2M);

5. The method of any of claims 3 or 4, wherein said QAM modulation is of order Q, Q-2^2qAnd q is a natural number.

6. A signal processing apparatus comprising:

the modulation module is used for carrying out QAM modulation on a bit block and outputting N/2 QAM symbols, wherein the bit block comprises a plurality of bits;

a conjugation module, configured to perform conjugation processing on the N/2 QAM symbols, and output N/2 conjugate symbols;

a mapping module, configured to map the N/2 QAM symbols to the 1 st to N/2 nd subcarriers in sequence, and map the N/2 conjugate symbols to the N/2+1 th to N th subcarriers in sequence according to a mapping order opposite to the N/2 QAM symbols;

where N is the number of subcarriers.

7. The apparatus of claim 6, wherein the QAM modulation is of order Q, Q-2^2qAnd q is a natural number.

8. A signal processing apparatus comprising:

the modulation module is used for carrying out QAM modulation on a bit block and outputting a plurality of QAM symbols, wherein the bit block comprises a plurality of bits;

a conjugation module, configured to perform conjugation processing on the multiple QAM symbols, and output multiple conjugate symbols;

the spread spectrum module is used for respectively carrying out spread spectrum processing on the QAM symbols and the conjugate symbols and outputting N/2 spread spectrum QAM symbols and N/2 spread spectrum conjugate symbols;

a mapping module, configured to sequentially map the N/2 spread QAM symbols to sub-carriers 1 to N/2, and sequentially map the N/2 spread conjugate symbols to sub-carriers N/2+1 to N according to a mapping order opposite to the N/2 spread QAM symbols;

where N is the number of subcarriers.

9. The apparatus of claim 8, wherein:

the QAM symbols are N/(2M), and the conjugate symbols are N/(2M);

10. The apparatus of any of claims 8 or 9, wherein said QAM modulation is of order Q, Q-2^2qAnd q is a natural number.