CN1464654A - Method for controlling bit after frame end insertion in OFDM communication system - Google Patents
Method for controlling bit after frame end insertion in OFDM communication system Download PDFInfo
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- CN1464654A CN1464654A CN 02113861 CN02113861A CN1464654A CN 1464654 A CN1464654 A CN 1464654A CN 02113861 CN02113861 CN 02113861 CN 02113861 A CN02113861 A CN 02113861A CN 1464654 A CN1464654 A CN 1464654A
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Abstract
The invention discloses a process for inserting control byte in the frame end of an OFDM communication system characterized by that, inserting the system information byte into the byte bit of the last OFDM which arrives last, then mapping the control information byte to the sub-carrier wave signal of the lowest frequency possible. The process stipulates the inserting position of the system control information byte and the mapped sub-carrier wave signal, warranting a relative short time delay and low code error rate in the transmission process. The invention can be used in the field of mobile communication system and wireless local area network based on OFDM.
Description
Technical field
The present invention can be applicable to wireless communication field, as mobile communication, WLAN (wireless local area network) etc., particularly adopts the wireless communication system of OFDM (OFDM) technology.
Background technology
The OFDM technology, it is information data demultiplexing with one group of two-forty, and be modulated on one group of subcarrier of pairwise orthogonal and send (Vijaya Chandran Ramasami, " Orthogonal Frequency Division Multiplexing " are seen in the OFDM general introduction).Because the OFDM technology has the superiority of anti-multipath time delay expansion, the OFDM technology will be widely used in the communication system of the high transfer rate in future.
General OFDM model such as Fig. 1 (see William Y.Zhou, Yiyan Wu, " COFDM:AnOverview ", and IEEE Transactions on Broadcasting, Vol.41, No.1, March 1995).As can be seen from Figure 1: the input data are through string and change after 1 every road x bit (in order to express easily, supposing that each circuit-switched data all is the x bit); Each circuit-switched data through mapping 2, obtains sub-carrier respectively; M sub-carrier through IFFT (inverse-Fourier transform) 3, and string conversion 4 and add protection time slot 5 after obtain 1 OFDM symbol.
In wireless communication system, the transmission of data is normally adopted in such a way: the data branch that send at different frames, different time slots, and is sent data according to certain frame format.
In multi-carrier wireless communications system, in order to guarantee communication quality, require as far as possible in time, transmission system control information reliably based on the high transfer rate of OFDM.The system control information bit is meant the system data of the required system's indication information of maintenance, maintain communications, reflection system running state etc., comprising power control bit, frame structure indication bit etc.And the system control information bit normally is inserted in the data flow, sends with data, therefore, must insert the control information bit rightly, makes that the propagation delay time of control information is little, the error rate is low.
The position of common insertion system information bit has 3 kinds: the middle part of frame head, frame, postamble.Insert control bit at frame head (or middle part of frame), following situation might occur:
During the insertion system information bit, send Frame and finished a part in sending Frame, system information has had little time to insert the frame head (or middle part of frame) of current transmission Frame, can only insert the next frame head (or middle part of frame) that sends Frame.So, the transmission of system information just is deferred to next Frame.
Existing method at controlling bit after frame end insertion in all designs at carrier wave communication system, as shown in Figure 2, does not consider the transmission characteristic of multi-carrier communications systems, so these methods and be not suitable for multi-carrier communications systems based on OFDM.
Analyze by principle, can learn:,, may cause the difference of the error rate at the subcarrier transmitting data of different frequency owing to adopted the OFDM technology to OFDM.For fear of the generation of above-mentioned situation, system information need be inserted into appropriate position, make that the error rate is low when the transmission system control information, time delay is little.
In sum, need design new frame structure form at transmission characteristic based on the multi-carrier communications systems of OFDM technology.
Summary of the invention
Task of the present invention provides a kind of method for controlling bit after frame end insertion in of ofdm communication system, it is the transmission characteristic at OFDM, by insertion position and the residing sub-carrier positions thereof of selecting appropriate system control information bit, make that the propagation delay time of system information is little, the error rate is low.
As previously mentioned, for every frame transmission system control information once,, might cause system control information to be delayed to next frame and just send if insert the head or the middle part of frame.For fear of this delay, select system control information is inserted into the afterbody of each frame, specific to last time slot of this frame, the last bit of last OFDM symbol.
By analyzing the transmission characteristic of OFDM technology, can know: in ofdm system, for the higher subcarrier of frequency, the intersymbol interference on the lower subcarrier of frequency is smaller.Therefore, the control information bit is placed on the lower subcarrier of frequency sends, the error rate during the transmission system control information is lower.
Method of the present invention is: at first every frame is sent control information once, be inserted into the last bit of last OFDM symbol M of last time slot K of this frame; Then the system control information bit is mapped on the alap sub-carrier of frequency.
Particularly, as Fig. 3, Fig. 4, suppose that the i frame has K time slot, time slot K has M OFDM symbol, and last OFDM symbol M has N bit: b
1, b
2B
N(b
1Arrive b at first
NReach at last).If the control information of i frame has y bit, so, the control information of this y bit will be inserted b
N-y+1B
NThese bits.The bit b that will comprise control information then
N-y+1B
NBeing mapped to the alap sub-carrier of frequency gets on.(among Fig. 3, Fig. 4, sub-carrier d
1Frequency minimum, d
2Secondly ..., d
MFrequency is the highest.)
At this moment the method for controlling bit after frame end insertion in of ofdm communication system of the present invention can be expressed as: send once control information for every frame, at first every frame is sent the last bit of last OFDM symbol M that once control information is inserted into last time slot K of this frame; With after the system information control bit process mapping (2), be put into the minimum sub-carrier (d of frequency then
1) on; If sub-carrier (d
1) can not load the system information control bit, remaining system information Control bit is put into frequency time low sub-carrier (d
2) on ..., and the like.
Sometimes out of need, a plurality of frames are formed a superframe.Thought of the present invention also can be used for the interleaved plan of the control bit of superframe.Particularly, in a certain superframe, insert system control information if desired, then these control informations are inserted last frame, last time slot of this superframe, the back-page bit of last OFDM symbol; Then control bit being mapped to the alap sub-carrier of frequency gets on.
In like manner, the thought of the present invention's proposition can also be used for the interleaved plan of the control bit of time slot.Particularly, insert control bit at a certain time slot if desired, the time that then these control bits is inserted into last OFDM symbol of this time slot is gone up the last bit that arrives; Then control bit being mapped to the alap sub-carrier of frequency gets on.
Need to prove that the method for controlling bit after frame end insertion in of ofdm communication system of the present invention requires to insert system information in present frame (or time slot, superframe), needn't wait until next frame (or time slot, superframe) ability insertion system information bit; The intersymbol interference of system information in the time of so just can reducing to transmit reduces the transmission error rates of system control information, thereby improves the reliability of system information transmissions.
In addition, sign map (modulation) unit 2 can adopt the modulation system of different rank for different subcarriers.
The present invention has following characteristics:
1. method is easy, reliable
Because in ofdm system, for the higher subcarrier of frequency, the intersymbol interference on the lower subcarrier of frequency is smaller.Method of the present invention is placed on the control information bit on the lower subcarrier of frequency and sends, the error rate during transmission system control information is very low, so come the insertion position of selective system information bit according to step of the present invention, can reach the target of " fast as far as possible and accurate ground delivery of system information ".
2. applied widely
The method for controlling bit after frame end insertion in of the ofdm communication system that the present invention proposes is applicable to the wireless communication field that uses the OFDM technology, comprises and may adopt the mobile communication system of OFDM technology future, and WLAN (wireless local area network) of two-forty, metropolitan area network or the like.
Description of drawings Fig. 1 is general OFDM model
Wherein, transmitter section: the 1st, string and converting unit, 2 is-symbols mapping (modulation) unit, the 3rd, IFFT unit, The 4th, parallel serial conversion unit, the 5th, add protection time slot unit, the 6th, D/A and low pass filter, the 7th, up-conversion, go to the sky The line unit; The 8th, wireless transmission channel; Receiver section: the 9th, down-converter unit, the 10th, A/D and low pass filter, 11 To remove protection time slot unit, the 12nd, FFT unit, the 13rd, single order balanced device, 14 is-symbols mapping (demodulation) unit. Fig. 2 is the scheme schematic diagram at controlling bit after frame end insertion in of single-carrier system
Wherein, F frame arranged in the superframe, every frame has K time slot, and each time slot has L modulation symbol, each accent Symbol processed is formed by the x bit modulation. System control information will be inserted into the upper last several bits that arrive of modulation symbol time The position.
As can be seen from the figure, every frame sends the last bit b of last OFDM symbol L that once control information is inserted into last time slot K of this frameNIf, last bit bNCan not load the system information control bit, remaining system information control bit is put into time last bit bN-1On ..., the like. Fig. 3 is the partial block diagram of the present invention from the input data to multi-carrier modulation
Wherein, bN…b
2b
1Input bit sequence (b1Arrive at first bNReach at last); d1，d
2，…d
MBe sub-carrier, sub-carrier frequencies is respectively: f1，f
2，…f
M, and f1＜f
2＜…＜f
M L is the OFDM symbol; The 15th, ratio Special plug-in unit, 2 is-symbols mapping (modulation) unit, in real system, the modulation bit number of each way carrier wave can With difference, the 16th, multiplier.
Among the figureI=1,2 ..., M, m=1,2 ..., M, the discrete carrier signal in the expression FFT,
The expression carrier signal
The sampled value that when m, engraves.
As can be seen from the figure: when the input data communication device is crossed the bit plug-in unit, insert control bit c at the end of datayc
y-1…c
2c
1, obtain one group of new data cyc
y-1…c
2c
1b
N-y…b
2b
1 Then this group data communication device is crossed string and conversion, Be assigned to (the every way carrier wave of hypothesis has the data of x bit among the figure) on each way carrier wave; With the data branch on each way carrier wave Tong Guo sign map (modulation) unit 2, be mapped to a plurality of sub-carrier d1，d
2，…d
M To include control at last The sub-carrier of bit (is d in the drawings1) (frequency of the subcarrier that the figure medium frequency is minimum is f to be modulated to the alap subcarrier of frequency1) get on. If sub-carrier d1Can not load the system information control bit, remaining system information control bit is put into frequency time low sub-carrier d2On ..., the like. So far, finished requirement of the present invention " with control ratio Special insertion postamble, and be mapped on the alap sub-carrier of frequency ". The control bit interleaved plan schematic diagram that Fig. 4 proposes for the present invention
Among the figure, F frame arranged in the superframe, every frame has K time slot, and each time slot has L OFDM symbol, and each OFDM symbol is by M sub-carrier (d1，d
2，…，d
M) form. Its sub-carriers d1Carrier frequency minimum, d2Secondly ..., dMCarrier frequency is the highest.
As can be seen from the figure, system control information will be inserted into the last bit b that arrives on the OFDM symbol timeN, the sub-carrier that will include then control bit (is d in the drawings1) (frequency of the subcarrier that the figure medium frequency is minimum is f to be modulated to the alap subcarrier of frequency1) get on. If sub-carrier d1Can not load the system information control bit, remaining system information control bit is put into frequency time low sub-carrier d2On ..., the like. So far, finished the present invention " control bit is inserted postamble, and is mapped on the alap sub-carrier of frequency " that requires.
Embodiment
As Fig. 3, Fig. 4, suppose that the i frame has K time slot, time slot K has M OFDM symbol, and last OFDM symbol M has N bit: b
1, b
2B
N(b
1Arrive b at first
NReach at last).If the control information of i frame has y bit, so, when data flow arrives, utilize bit insertion technology, b is inserted in the control information of this y bit
N-y+1B
NThese bits, these control bits enter sign map unit (being a plurality of multi-system modulators) with information bit as data bit flow; The bit b that will comprise control information then
N-y+1B
NBeing mapped to the alap sub-carrier of frequency gets on.(among Fig. 3, Fig. 4, sub-carrier d
1Frequency minimum, d
2Secondly ..., d
MFrequency is the highest.)
Bit wherein inserts technology, sign map technology, all is mature technique, and the relevant hardware support is arranged.Therefore, utilize present technological means, the method for controlling bit after frame end insertion in of the ofdm communication system that is easy to realize that the present invention proposes.
Claims (3)
1. the method for controlling bit after frame end insertion in of an ofdm communication system, send once control information bit, the step below carrying out for every frame: at first every frame is sent the last bit of last OFDM symbol M that once control information bit is inserted into last time slot K of this frame; After it is characterized in that then system information control bit process being shone upon (2), be put into the minimum sub-carrier (d of frequency
1) on; If sub-carrier (d
1) can not load the system information control bit, remaining system information Control bit is put into frequency time low sub-carrier (d
2) on ..., and the like.
2. the method for controlling bit after frame end insertion in of an ofdm communication system, for in a certain superframe, inserting the system control information bit, the step below carrying out: at first these control information bits are inserted last frame, last time slot of this superframe, the back-page bit of last OFDM symbol; After it is characterized in that then system information control bit process being shone upon (2), be put into the minimum sub-carrier (d of frequency
1) on; If sub-carrier (d
1) can not load the system information control bit, remaining system information Control bit is put into frequency time low sub-carrier (d
2) on ..., and the like.
3. the method for controlling bit after frame end insertion in of an ofdm communication system, for inserting control bit at a certain time slot, it is that the time that these control bits are inserted into last OFDM symbol of this time slot is gone up the last bit that arrives; After it is characterized in that then system information control bit process being shone upon (2), be put into the minimum sub-carrier (d of frequency
1) on; If sub-carrier (d
1) can not load the system information control bit, remaining system information Control bit is put into frequency time low sub-carrier (d
2) on ..., and the like.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021138613A CN100414859C (en) | 2002-06-12 | 2002-06-12 | Method for controlling bit after frame end insertion in OFDM communication system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021138613A CN100414859C (en) | 2002-06-12 | 2002-06-12 | Method for controlling bit after frame end insertion in OFDM communication system |
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| Publication Number | Publication Date |
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| CN1464654A true CN1464654A (en) | 2003-12-31 |
| CN100414859C CN100414859C (en) | 2008-08-27 |
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ID=29742257
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| WO2008046268A1 (en) * | 2006-10-16 | 2008-04-24 | Zte Corporation | A method for fault tolerating in the mobile multimedia broadcast system |
| WO2008116353A1 (en) * | 2007-03-28 | 2008-10-02 | Zte Corporation | A base station, frame structure and synchronization channel transmittion method for time division duplex systems |
| CN100456659C (en) * | 2006-08-09 | 2009-01-28 | 北京泰美世纪科技有限公司 | Method for sending control information to indicate operation of receiver |
| CN100466815C (en) * | 2006-03-14 | 2009-03-04 | 华为技术有限公司 | Method for distributing GSM adjacent zone frequency point and structuring GSM adjacent zone list |
| CN101175058B (en) * | 2006-10-31 | 2010-05-19 | 中兴通讯股份有限公司 | Synchronous channel transmission method of TDD system |
| CN101114877B (en) * | 2007-03-12 | 2010-12-08 | 中兴通讯股份有限公司 | Enhanced synchronous channel transmitting method |
| CN101163122B (en) * | 2006-10-09 | 2011-08-10 | 中兴通讯股份有限公司 | Method of transmitting TDD system control information |
| CN101562476B (en) * | 2008-04-16 | 2013-02-27 | 中兴通讯股份有限公司 | Design and transmission method for control channel in wireless communication system |
| CN101018221B (en) * | 2006-02-10 | 2013-05-01 | 中兴通讯股份有限公司 | Signal sending method of OFDM system and cell searching method |
| CN107455002A (en) * | 2015-05-05 | 2017-12-08 | 华为技术有限公司 | The transmission method and device of physical layer protocol data unit |
| WO2019137314A1 (en) * | 2018-01-15 | 2019-07-18 | ***通信有限公司研究院 | Information transmission and reception method, network equipment, and user equipment |
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| KR100362571B1 (en) * | 1999-07-05 | 2002-11-27 | 삼성전자 주식회사 | Frequency offset compensation apparatus and method using pilot symbol in orthogonal frequency division multiplex system |
| JP3581072B2 (en) * | 2000-01-24 | 2004-10-27 | 株式会社エヌ・ティ・ティ・ドコモ | Channel configuration method and base station using the method |
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| CN101018221B (en) * | 2006-02-10 | 2013-05-01 | 中兴通讯股份有限公司 | Signal sending method of OFDM system and cell searching method |
| CN100466815C (en) * | 2006-03-14 | 2009-03-04 | 华为技术有限公司 | Method for distributing GSM adjacent zone frequency point and structuring GSM adjacent zone list |
| CN100456659C (en) * | 2006-08-09 | 2009-01-28 | 北京泰美世纪科技有限公司 | Method for sending control information to indicate operation of receiver |
| CN101163122B (en) * | 2006-10-09 | 2011-08-10 | 中兴通讯股份有限公司 | Method of transmitting TDD system control information |
| WO2008046268A1 (en) * | 2006-10-16 | 2008-04-24 | Zte Corporation | A method for fault tolerating in the mobile multimedia broadcast system |
| CN101175058B (en) * | 2006-10-31 | 2010-05-19 | 中兴通讯股份有限公司 | Synchronous channel transmission method of TDD system |
| CN101114877B (en) * | 2007-03-12 | 2010-12-08 | 中兴通讯股份有限公司 | Enhanced synchronous channel transmitting method |
| WO2008116353A1 (en) * | 2007-03-28 | 2008-10-02 | Zte Corporation | A base station, frame structure and synchronization channel transmittion method for time division duplex systems |
| CN101562476B (en) * | 2008-04-16 | 2013-02-27 | 中兴通讯股份有限公司 | Design and transmission method for control channel in wireless communication system |
| CN107455002A (en) * | 2015-05-05 | 2017-12-08 | 华为技术有限公司 | The transmission method and device of physical layer protocol data unit |
| CN107455002B (en) * | 2015-05-05 | 2020-07-14 | 华为技术有限公司 | Method and device for transmitting physical layer protocol data unit |
| US10812307B2 (en) | 2015-05-05 | 2020-10-20 | Huawei Technologies Co., Ltd. | Physical layer protocol data unit transmission method and apparatus |
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| CN110115008A (en) * | 2016-12-07 | 2019-08-09 | Lg电子株式会社 | The method and apparatus for configuring the control channel of the NR in wireless communication system |
| CN110115008B (en) * | 2016-12-07 | 2021-11-16 | Lg电子株式会社 | Method and apparatus for configuring control channel of NR in wireless communication system |
| WO2019137314A1 (en) * | 2018-01-15 | 2019-07-18 | ***通信有限公司研究院 | Information transmission and reception method, network equipment, and user equipment |
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| CN100414859C (en) | 2008-08-27 |
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