CN100512249C - Method of orthogonal FDM for modulatng sub-carrier separation and sub-band cross arrangement - Google Patents
Method of orthogonal FDM for modulatng sub-carrier separation and sub-band cross arrangement Download PDFInfo
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- CN100512249C CN100512249C CNB2004100170225A CN200410017022A CN100512249C CN 100512249 C CN100512249 C CN 100512249C CN B2004100170225 A CNB2004100170225 A CN B2004100170225A CN 200410017022 A CN200410017022 A CN 200410017022A CN 100512249 C CN100512249 C CN 100512249C
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Abstract
Using characters of periodic fading of channel in frequency selectivity, the invented method partitions orthogonal FDM modulation sub carrier wave into some sub bands in two types crossed arranged to be assigned to two typed users. Self-adapting allotting technique is adopted for one typed users, and orthogonal FDM modulated transmission technique is adopted for another type users. Sub bands in two types crossed arranged occupies all sub carrier wave of effective data. Transmitting terminal maps data of the two typed user into relevant sub carrier wave. The method reduces amount of information fed back from system needed and considering need of general users in speech sound class.
Description
Technical field
The present invention relates to be used for digital information transmission technical field, be specifically related to a kind of OFDM modulation (OFDM) subcarrier and cut apart method with the subband cross arrangement.
Background technology
In the IEEE802.16 agreement, the sub carrier group of distributing to the user is made of subcarrier separated by a distance, purpose is to make all subcarriers of distributing to same user can not be in deep fade simultaneously, guarantee that the user transmits the minimum quality requirement of information, but to the user of need big data quantity or video transmission, quality can't guarantee.
In the multipath channel transmission, the characteristics of channel frequence of exposure selectivity decline, the bit error rate performance of each subcarrier is determined by the frequency domain channel impulse response in the OFDM symbol, bit error mainly appears on the subcarrier that is in deep fade, in the OFDM symbol, identified out with the subcarrier that is in deep fade if frequency domain impulse response gain is maximum, and correspondingly increase or the minimizing transmitted data amount, then under the little situation of system capacity loss, the overall bit-error rate performance will improve.Said method belongs to the adaptive subcarrier distribution technique, is used for the user who needs big data quantity or video transmission is provided the protection of better quality.If use the adaptive subcarrier distribution technique in whole transmission band, the amount of overhead of system feedback information is very big, simultaneously the user who needs big data quantity or video transmission is used this technology, and transmission quality could obviously improve; To general voice class user, owing to taken the influence of sub-carrier number and motion velocity of mobile station, the adaptive subcarrier distribution technique can't effectively use, and therefore, is necessary whether adopt adaptive technique according to user's kind compartment system.On the other hand, if the shared spuious arrangement of subcarrier of various types of user, the expense of system's indication information will be huger.
Find by literature search, " Adaptive ModulationTechniques for Duplex OFDM Transmission " (IEEE TRANSACTIONS ONVEHICULAR TECHNOLOGY that people such as Thomas Keller deliver, VOL.49, NO.5, SEPTEMBER 2000, " adaptive modulation technology in the transmission of duplexing OFDM ") in the literary composition, mentioned and adopted the adaptive subcarrier modulation technique that the Frequency points of different declines on the frequency domain are adopted different modulation systems.The criterion of choosing is that the gain of frequency domain channel impulse response size is compared with thresholding.This method also is known as prerequisite with the frequency domain channel impulse response of receiving terminal making a start, and promptly in ofdm system, the modulating mode of all valid data subcarriers all will transmit to transmitting terminal from receiving terminal, and this has increased great burden to information indication link.On the other hand, in multi-user system, which user a certain subcarrier should be distributed to, should adopt which kind of modulation system, all will comprehensively judge at transmitting terminal.The burden of message transmission will further increase.
Summary of the invention
The objective of the invention is at application self-adapting subcarrier allocation technology how efficiently in the orthogonal FDM modulation system, propose a kind of OFDM modulated sub-carriers and cut apart method with the subband cross arrangement, by the OFDM modulated sub-carriers being divided into two class subbands of some cross arrangements, make it reduce the system feedback amount of information that adaptive subcarrier divides the timing needs, taken into account general voice class user's demand simultaneously.
The present invention is achieved by the following technical solutions, the present invention utilizes the characteristics of frequency-selective channel cycle decline, the OFDM subcarrier is divided into two class subbands of some cross arrangements, and distribute to two class users of different demands, one class user adopts the self adaptation distribution technique, and another kind of user adopts general OFDM transmission technology; For avoiding the damaging influence of single-frequency interference to a certain type subband, the discharging of two class subband sequence alternates is taken all valid data subcarriers, at transmitting terminal dissimilar user's data are mapped on its corresponding subcarrier.
Below the present invention is further illustrated, may further comprise the steps:
1) the valid data subcarrier in the OFDM subcarrier is divided into 2N subband (subband is meant the subcarrier set that is made of several adjacent sub-carriers) continuously herein, wherein N is a positive integer;
2) N subband distributed to the voice class user in 2N subband, and N subband distributed to data and video class user;
3) voice class subband and data and video class subband sequence alternate discharging takies the valid data subcarrier in the whole OFDM subcarrier;
4) user profile is being made a start by the differentiation classification, just voice class subband and data and video class subband, after error correction coding separately, carry out symbol-modulated and be mapped on the subcarrier in such small pin for the case band according to its classification, with common control information, zero sideband, pilot tone is formed a complete OFDM symbol, gives Channel Transmission through IFFT, insertion Cyclic Prefix, shaping filter, digital to analog conversion, rf conversion after handling, and carries out the respective classified reception by receiving end and handles.
Compared with prior art, the present invention is according to the characteristics of frequency-selective channel cycle decline, the OFDM subcarrier is divided into the subband of cross arrangement, and distribute to the user of different demands, this method has reduced the system feedback amount of information that adaptive subcarrier divides the timing needs, has taken into account general voice class user's demand simultaneously.
Description of drawings
Fig. 1 is in OFDM valid data subcarrier, and the subband sequence alternate discharges schematic diagram during N=2
Embodiment
For understanding technical scheme of the present invention better, be further described below in conjunction with accompanying drawing:
The present invention carries out following steps making a start:
(1) with ofdm system valid data subcarrier sequence arrangement;
Above-mentioned subcarrier is divided into 4 continuous subbands;
In (2) 4 subbands, distribute to the voice class user for 2, distribute to data and video class user for 2;
(3) these 4 subbands of cross arrangement, pattern of rows and columns can comprise two kinds: voice class, data and video class, voice class, data and video class (as shown in Figure 1) and data and video class, voice class, data and video class, voice class;
(4) information with general voice class user is mapped to the voice class subband after Turbo product coding and QAM modulation, and data and video class subband are modulated and be mapped to data and video class user's information according to the indicating mode of adaptive subcarrier modulation after the Turbo product coding;
Above-mentioned valid data subcarrier and common control information, zero sideband, pilot tone is formed a complete OFDM symbol, generate 1024 time-domain signals through 1024 IFFT, last 256 with 1024 time-domain signals are duplicated, and the front that is filled into 1024 time-domain signals forms 1280 time-domain signals, promptly insert Cyclic Prefix, subsequently, through forming filter, 1280 time-domain signals are carried out filtering, and become analog signal through 8 digital to analog conversion, at last, rf conversion is given Channel Transmission after handling baseband signal being transformed to the carrier frequency of 2.4GHz, carries out respective classified by receiving end and receives and handle.
Ofdm system with 1024 FFT is an example, and system comprises 64 users, 56 voice class users wherein, 8 data and video class user.When frequency band was not distinguished, system's indication information needed 1024 * 64 indication units, and after frequency band was distinguished, system's indication information needed 512 * 8 indication units, reduces 16 times.
Claims (3)
1, a kind of OFDM modulated sub-carriers is cut apart the method with the subband cross arrangement, it is characterized in that, utilize the characteristics of frequency-selective channel cycle decline, the OFDM modulated sub-carriers is divided into two class subbands of some cross arrangements, and distribute to two class users, one class user adopts the self adaptation distribution technique, another kind of user adopts the OFDM modulation-transmission technology, the discharging of two class subband sequence alternates takes all valid data subcarriers, at transmitting terminal two types of user's data is mapped on its corresponding subcarrier.
2, OFDM modulated sub-carriers according to claim 1 is cut apart the method with the subband cross arrangement, it is characterized in that, below the present invention is done further qualification, may further comprise the steps:
1) the valid data subcarrier in the OFDM modulated sub-carriers is divided into 2N subband continuously, subband is meant the subcarrier set that is made of several adjacent sub-carriers herein, and wherein N is a positive integer;
2) N subband distributed to the voice class user in 2N subband, and N subband distributed to data and video class user;
3) voice class subband and data and video class subband sequence alternate discharging takies the valid data subcarrier in the whole OFDM modulated sub-carriers;
4) user profile is being made a start by the differentiation classification, after error correction coding, carry out symbol-modulated and be mapped on the subcarrier in such small pin for the case band according to its classification, form a complete OFDM modulation symbol with common control information, zero sideband, pilot tone, give Channel Transmission after handling through IFFT, insertion Cyclic Prefix, shaping filter, digital to analog conversion, rf conversion.
3, OFDM modulated sub-carriers according to claim 1 is cut apart the method with the subband cross arrangement, it is characterized in that, described valid data subcarrier, itself and common control information, zero sideband, pilot tone is formed a complete OFDM symbol, generate 1024 time-domain signals through 1024 IFFT, last 256 with 1024 time-domain signals are duplicated, and the front that is filled into 1024 time-domain signals forms 1280 time-domain signals, promptly insert Cyclic Prefix, subsequently, through forming filter, 1280 time-domain signals are carried out filtering, and become analog signal through 8 digital to analog conversion, last, rf conversion is given Channel Transmission after handling baseband signal being transformed to the carrier frequency of 2.4GHz, carries out respective classified by receiving end and receives and handle.
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| CN100512249C true CN100512249C (en) | 2009-07-08 |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| FR2883681A1 (en) * | 2005-03-23 | 2006-09-29 | France Telecom | METHOD FOR ALLOCATING SUBWAYS TO MULTI-CHANNEL LINK STREAMS IN A MULTI-CHANNEL MODULATION COMMUNICATION SYSTEM |
| CN101051878B (en) * | 2006-04-06 | 2013-01-30 | 华为技术有限公司 | Method and device for realizing channel feedback in communication system |
| CN101094215B (en) * | 2006-06-22 | 2010-09-29 | 中兴通讯股份有限公司 | Self-adaptive method for allotting sub carriers in orthogonal frequency division multiplexing multiple access system |
| CN102307086B (en) * | 2011-08-19 | 2017-03-15 | 中兴通讯股份有限公司 | Based on method and communication terminal that carrier aggregation technology realizes mixed communication |
| CN113258940B (en) * | 2021-06-15 | 2021-10-08 | 成都星联芯通科技有限公司 | turbo decoding method, turbo decoding device, turbo decoding apparatus, and storage medium |
| CN115173958B (en) * | 2022-06-30 | 2024-03-22 | 桂林电子科技大学 | Method for realizing unequal error protection of underwater multimedia data transmission based on optical OFDM |
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Non-Patent Citations (4)
| Title |
|---|
| 一种基于最大容量的多载波系统自适应调制和功率分配算法. 赵亚红，张忠培，吴伟陵.电子与信息学报，第25卷第7期. 2003 |
| 一种基于最大容量的多载波系统自适应调制和功率分配算法. 赵亚红，张忠培，吴伟陵.电子与信息学报，第25卷第7期. 2003 * |
| 基于OFDM的自适应传输技术. 李真，王伟华，周文安，宋俊德.无线电通信技术，第30卷第1期. 2004 |
| 基于OFDM的自适应传输技术. 李真，王伟华，周文安，宋俊德.无线电通信技术，第30卷第1期. 2004 * |
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