CN203872203U - Code division multiplexing quadrature frequency division multiple access communication system signal emitting device - Google Patents

Abstract

Provided is a code division multiplexing quadrature frequency division multiple access communication system signal emitting device. A first grade pseudo code spread spectrum unit and a second grade multicarrier quadrature modulation unit in the device comprise a plurality of sub-channels respectively. Each sub-channel is composed of a signal multiplier. The amount of the sub-channels of the first grade pseudo code spread spectrum unit is the same as the amount of the second grade multicarrier quadrature modulation unit. The outputs of the sub-channels of the first grade pseudo code spread spectrum unit are connected with the inputs of the sub-channels of the second grade multicarrier quadrature modulation unit. An output of a symbol insertion module is connected with a data symbol reuse module. The output of the data symbol reuse module is connected with a data flow serial-to-parallel conversion module. The data flow serial-to-parallel conversion module comprises a plurality of parallel outputs. Each output is connected with the signal multiplier in one sub-channel of the first grade pseudo code spread spectrum unit and the signal multiplier in one sub-channel of the second grade multicarrier quadrature modulation unit in order. The outputs of all the sub-channels in the second grade multicarrier quadrature modulation unit are connected with a subcarrier signal synthesis module. The output of the subcarrier signal synthesis module is connected with a DAC and upconversion module and a radio-frequency emission front-end module in order.

Description

Code division multiplexing ofdma communication system sender unit

Technical field

The utility model belongs to mobile communication technology field, relates to a kind of emitter of realizing code division multiplexing ofdma communication system.

Background technology

Code division multiplexing/CDMA communication system generally has very high channel width, but anti-multipath jamming performance is poor, in real system, conventionally adopt and reduce the method for bit rate or utilize narrow band transmission, the voice data transmission of for example using in GlobalStar is a kind of arrowband spread spectrum communication that only can support 10kbps magnitude.

OFDM/orthogonal frequency division multiple access communication system is widely used in land mobile communication system, being described as is the band wagon technique of following next generation wireless communication (4G), this technology itself designs for solving multipath disturbs, by multi-carrier transmission, can support higher data transfer rate, 100Mbps is even higher, in addition, owing to having adopted orthogonal multiple carrier transmission technology, its frequency spectrum can be overlapping, greatly promoted the effective rate of utilization of frequency resource, this seems particularly valuable under the limited communication condition of the frequency spectrum resources such as satellite communication.

At present, Related Research Domain is generally divided code with two kinds of systems of orthogonal frequency and is combined by the mode of alternative both at home and abroad, selector switch and processor module are set in system emitter, by switching over, select transmission code to divide or orthogonal frequency signal, by processor module to signal transmission encode accordingly, modulation, the operation such as multiplexing, and identical module also to be set in system receiving system; This system is very complicated, cost is higher, and switching over once can only be selected single kind of transmission mode, can not really realize and code be divided to combine with two kinds of systems of orthogonal frequency be the compatible design philosophy of mixed transport, the mode of this alternative is difficult to adapt to development need current and future communications system compatibility and autgmentability.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome prior art deficiency, provide a kind of for realizing the emitter of code division multiplexing ofdma communication system.Adopt the utility model to realize code is divided that to combine with two kinds of systems of orthogonal frequency be mixed transport, device design is brief, and cost is lower, convenient and practical.

Technical solution of the present invention is: code division multiplexing ofdma communication system sender unit, comprise symbol insert module, data symbol Multiplexing module, data flow serial to parallel conversion module, first order Pseudo Code Spread Spectrum unit, second level multi-carrier orthogonal modulating unit, subcarrier signal synthesis module, DAC and up-converter module and radio-frequency transmissions front-end module;

Described first order Pseudo Code Spread Spectrum unit and second level multi-carrier orthogonal modulating unit comprise respectively multiplex subchannel, every sub-channels consists of a signal multiplier, the quantity of the two subchannel is consistent, and the output of first order Pseudo Code Spread Spectrum unit subchannel connects the input of second level multi-carrier orthogonal modulating unit subchannel; Symbol insert module connection data symbol Multiplexing module, data symbol Multiplexing module connection data stream serial to parallel conversion module; Data flow serial to parallel conversion module has Parallel multiplex output end, every road output connects respectively the signal multiplier in first order Pseudo Code Spread Spectrum unit and second level multi-carrier orthogonal modulating unit one sub-channels successively, the output auxiliary connection carrier signal synthesis module of all subchannels in the multi-carrier orthogonal modulating unit of the second level, the output of subcarrier signal synthesis module connects DAC and up-converter module and radio-frequency transmissions front-end module successively;

Symbol insert module formats multi-user's symbol data of input, and inserts frequency pilot sign in symbol data, obtains serial raw data symbols and inputs to data symbol Multiplexing module, data symbol Multiplexing module to serial raw data symbols pack, synthesize, framing, form serial multiplex data symbol stream, data flow serial to parallel conversion module is changed to parallel duplex transmission by the rheology of serial multiplex data symbol, signal multiplier Jiang Mei road output in first order Pseudo Code Spread Spectrum unit is carried out multiplying with the local Pseudo Code Spread Spectrum signal generating, obtain code division multiplexing subcarrier signal, signal multiplier in the multi-carrier orthogonal modulating unit of the second level carries out quadrature modulation by code division multiplexing subcarrier signal, obtain OFDM subcarrier signal, subcarrier signal synthesis module Jiang Mei road OFDM subcarrier signal synthesizes a road signal, this road signal is processed into radiofrequency signal through DAC and up-converter module, by radio-frequency transmissions front-end module, send this radiofrequency signal.

The present invention compared with prior art beneficial effect is:

(1) the utility model can divide code with two kinds of signal systems of orthogonal frequency and combines, and generates code division multiplexing OFDM mixed signal and also realizes mixed transport, has effectively expanded the compatible property of two kinds of communication systems.

(2) the utility model adopts two-stage Pseudo Code Spread Spectrum and multi-carrier orthogonal modulation component unit (after first spread spectrum, modulating) in the functional module of emitter, realized the generation of Pseudo Code Spread Spectrum signal, and the code division multiplex signal after spread spectrum has been realized to multi-carrier orthogonal modulation, thereby generated the code division multiplexing OFDMA signal mixing.

Accompanying drawing explanation

Fig. 1 is the utility model schematic diagram;

Fig. 2 is the utility model Pseudo Code Spread Spectrum and multi-carrier orthogonal modulation component unit schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, structure of the present utility model is described.Code division multiplexing ofdma communication system sender unit, comprise as shown in Figure 1 symbol insert module, data symbol Multiplexing module, data flow serial to parallel conversion module, first order Pseudo Code Spread Spectrum unit, second level multi-carrier orthogonal modulating unit, subcarrier signal synthesis module, DAC and up-converter module and radio-frequency transmissions front-end module;

As shown in Figure 2, first order Pseudo Code Spread Spectrum unit and second level multi-carrier orthogonal modulating unit comprise respectively multiplex subchannel, every sub-channels consists of a signal multiplier, the quantity of the two subchannel is consistent, and the output of first order Pseudo Code Spread Spectrum unit subchannel connects the input of second level multi-carrier orthogonal modulating unit subchannel; Symbol insert module connection data symbol Multiplexing module, data symbol Multiplexing module connection data stream serial to parallel conversion module; Data flow serial to parallel conversion module has Parallel multiplex output end, every road output connects respectively the signal multiplier in first order Pseudo Code Spread Spectrum unit and second level multi-carrier orthogonal modulating unit one sub-channels successively, the output auxiliary connection carrier signal synthesis module of all subchannels in the multi-carrier orthogonal modulating unit of the second level, the output of subcarrier signal synthesis module connects DAC and up-converter module and radio-frequency transmissions front-end module successively;

Symbol insert module is responsible for multi-user's raw data symbols to format, and in data symbol, insert frequency pilot sign, frequency pilot sign is one group of definite known signal, is used in receiving equipment, accurately implementing parameter Estimation and compensating equalization, realizes the reconstruction and the recovery that receive data symbol.

Data symbol Multiplexing module be responsible for by serial raw data symbols pack, synthesize, the operation such as framing, and form serial multiplex data symbol stream.

It is parallel multichannel (N road) transmission from the single road propagation and transformation of serial that data flow serial to parallel conversion module is responsible for raw data symbols stream, wherein each road is as a sub-channels, the first via is defined as the 0th subchannel, the second tunnel is defined as the 1st subchannel, Third Road is defined as the 2nd subchannel, by that analogy, to N road, be defined as N-1 subchannel, by the data symbol on each road, give Pseudo Code Spread Spectrum and multi-carrier orthogonal modulation component unit is processed.General N is value in several numerical value such as 64,128,256,512,1024.

First order Pseudo Code Spread Spectrum unit is responsible for the data symbol on each road to carry out Pseudo Code Spread Spectrum, by one group of pseudorandom spread spectrum code character (Gold sequence), realizes, and each the road raw data symbols after spread spectrum becomes code division multiplexing subcarrier signal.

Second level multi-carrier orthogonal modulating unit is responsible for the code division multiplexing subcarrier signal on each road to carry out quadrature modulation, by quadrature IFFT operation, realizes, and after modulation, the code division multiplexing subcarrier signal on each road becomes OFDM subcarrier signal.

Subcarrier signal synthesis module is responsible for that the parallel subcarrier signal in N road is added to a synthetic road composite signal and is carried, and this signal is the code division multiplexing OFDM of generation and mixes subcarrier signal.

DAC and up-converter module, radio-frequency transmissions front-end module have been responsible for a series of map functions from subcarrier signal to radiofrequency signal, comprise digital-to-analogue conversion, up-conversion, power amplification, transmitting filtering, the operations such as frequency multiplication transmitting.This signal can be gone to terrestrial wireless mobile communications network and/or satellite mobile communication network by the transmitting of radio-frequency transmissions front-end module.

As shown in Figure 2, first order Pseudo Code Spread Spectrum unit, input is the subchannel consisting of N road raw data symbols, each road all adopts a Pseudo Code Spread Spectrum signal generator consisting of signal multiplier, and this multiplier is responsible for the data symbol on each road and the local Pseudo Code Spread Spectrum signal generating to carry out multiplying.

Every signal multiplier on the way all has identical structure, and the pseudorandom spread spectrum code that every this locality on the way generates is also identical, and meets the requirement of pseudo noise code orthogonal spectrum expansion.

If the raw data symbols on each road is Pn, after the Pseudo Code Spread Spectrum of spread spectrum module, obtaining spread-spectrum signal dn can be calculated by formula [1]:

d _n=P _n×C(0) [1]

In formula [1], C (0) represents the Gold type spread-spectrum pseudo code that the local code length producing is L.

Second level multi-carrier orthogonal modulating unit, input is the subchannel that the code division multiplexing subcarrier signal that generated after Pseudo Code Spread Spectrum by N road forms, each road all adopts a multi-carrier orthogonal modulator consisting of signal multiplier, and this signal multiplier is responsible for the code division multiplexing subcarrier signal on each road and the local coherent carrier generating to carry out multiplying.

Every signal multiplier on the way all has identical structure, and the coherent carrier that every this locality on the way generates is different, by one group of multi-subcarrier f ₀, f ₁, f ₂..., f _n-1modulate with every code division multiplexing subcarrier signal on the way respectively, and meet the requirement of multi-carrier orthogonal.

Code division multiplexing subcarrier signal d for each road _n, through the modulation of multi-carrier orthogonal modulation module, and the code division multiplexing OFDM generating after subcarrier signal synthesis module is synthetic mixing subcarrier output signal S (t), available formula [2] is calculated:

$S\left(t\right)=\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}{d}_k\×\exp \left(j2\mathrm{\π}{f}_{k}t\right)---\left[2\right]$

This mixing subcarrier output signal S (t) will be transported to ground and/or satellite communication channel transmission through radio-frequency transmissions front-end module, finally arrive user terminal.

The unspecified part of the utility model belongs to general knowledge as well known to those skilled in the art

Claims (1)

1. code division multiplexing ofdma communication system sender unit, it is characterized in that: comprise symbol insert module, data symbol Multiplexing module, data flow serial to parallel conversion module, first order Pseudo Code Spread Spectrum unit, second level multi-carrier orthogonal modulating unit, subcarrier signal synthesis module, DAC and up-converter module and radio-frequency transmissions front-end module;

Described first order Pseudo Code Spread Spectrum unit and second level multi-carrier orthogonal modulating unit comprise respectively multiplex subchannel, every sub-channels consists of a signal multiplier, the quantity of the two subchannel is consistent, and the output of first order Pseudo Code Spread Spectrum unit subchannel connects the input of second level multi-carrier orthogonal modulating unit subchannel; Symbol insert module connection data symbol Multiplexing module, data symbol Multiplexing module connection data stream serial to parallel conversion module; Data flow serial to parallel conversion module has Parallel multiplex output end, every road output connects respectively the signal multiplier in first order Pseudo Code Spread Spectrum unit and second level multi-carrier orthogonal modulating unit one sub-channels successively, the output auxiliary connection carrier signal synthesis module of all subchannels in the multi-carrier orthogonal modulating unit of the second level, the output of subcarrier signal synthesis module connects DAC and up-converter module and radio-frequency transmissions front-end module successively;

Symbol insert module formats multi-user's symbol data of input, and inserts frequency pilot sign in symbol data, obtains serial raw data symbols and inputs to data symbol Multiplexing module, data symbol Multiplexing module to serial raw data symbols pack, synthesize, framing, form serial multiplex data symbol stream, data flow serial to parallel conversion module is changed to parallel duplex transmission by the rheology of serial multiplex data symbol, signal multiplier Jiang Mei road output in first order Pseudo Code Spread Spectrum unit is carried out multiplying with the local Pseudo Code Spread Spectrum signal generating, obtain code division multiplexing subcarrier signal, signal multiplier in the multi-carrier orthogonal modulating unit of the second level carries out quadrature modulation by code division multiplexing subcarrier signal, obtain OFDM subcarrier signal, subcarrier signal synthesis module Jiang Mei road OFDM subcarrier signal synthesizes a road signal, this road signal is processed into radiofrequency signal through DAC and up-converter module, by radio-frequency transmissions front-end module, send this radiofrequency signal.