CN103095640A - Method for improving synchronous accuracy of high-speed mobile orthogonal frequency division multiplexing (OFDM) system - Google Patents
Method for improving synchronous accuracy of high-speed mobile orthogonal frequency division multiplexing (OFDM) system Download PDFInfo
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- CN103095640A CN103095640A CN2013100672536A CN201310067253A CN103095640A CN 103095640 A CN103095640 A CN 103095640A CN 2013100672536 A CN2013100672536 A CN 2013100672536A CN 201310067253 A CN201310067253 A CN 201310067253A CN 103095640 A CN103095640 A CN 103095640A
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Abstract
The invention discloses a method for improving synchronous accuracy of a high-speed mobile OFDM system. The method comprises the steps of carrying out pre-emphasis on a short training sequence in a wireless local area network protocol frame structure, and determining a synchronous position according to the short training sequence after being previously emphasized and a long training sequence in the wireless local area network protocol frame structure. The method for improving the synchronous accuracy of the high-speed mobile OFDM system can improve the ability to resist channel quick time selective fading, and can improve the synchronous accuracy of the OFDM system.
Description
Technical field
The present invention relates to the communication technology, relate in particular to a kind of method that improves the synchronous accuracy of high-speed moving OFDM system.
Background technology
One of core technology of intelligent transportation system is exactly the short range communication system (claiming again the special short distance communication, Dedicated Short Range Communications, DSRC) that is applicable to field of traffic.In various traffic dedicated short range communication systems, IEEE 802.11pTM/D5.0, the following general designation of November 2008(IEEE802.11p) standard is paid attention to its superior performance, and a plurality of countries indicate the implementation criteria of IEEE 802.11p as inter-vehicle communication.
In the situation that high-speed mobile, the quick time selective fading of channel makes OFDM (Orthogonal Frequency Division Multiplexing is called for short OFDM) system be difficult to obtain accurate synchronization.Therefore, just can improve the accuracy of system synchronization if can reduce the quick time selective fading of channel.
Summary of the invention
The invention provides a kind of method that improves the synchronous accuracy of high-speed moving OFDM system, in order to improve the ability of the quick time selective fading of antagonism channel, improve the synchronous accuracy of ofdm system.
The invention provides a kind of method that improves the synchronous accuracy of high-speed moving OFDM system, comprising:
Short training sequence in the protocol of wireless local area network frame structure is carried out preemphasis;
Determine sync bit according to long training sequence in the short training sequence after preemphasis and protocol of wireless local area network frame structure.
In one embodiment, the short training sequence in the protocol of wireless local area network frame structure is carried out preemphasis, is specially:
The following mode that adopts is carried out preemphasis with the amplitude of short training sequence:
X(d)=R(d)+P(d)*R(d)
Wherein, X (d) is the short training sequence after preemphasis, and R (d) is the short training sequence of protocol of wireless local area network regulation, P (d)=a*Mod (d), and the increase the weight of pattern of Mod (d) for selecting, d=0 ... L-1; L ..., L+L-1; L+8*L ..., L+9*L-1, L are the bit number that single short training sequence comprises, a is the amplitude of preemphasis, preferred 0≤a ﹤ 1.
In another embodiment, determine sync bit according to long training sequence in the short training sequence after preemphasis and protocol of wireless local area network frame structure, comprising:
Utilize the short training sequence of the preemphasis of a plurality of repetitions to determine thick synchronous position;
From thick sync bit, utilize the short training sequence of preemphasis to carry out carefully synchronizeing with the irrelevance of long training sequence, obtain thin sync bit.
The present invention is by carrying out preemphasis with the short training sequence in the protocol of wireless local area network frame structure, make ofdm system can not revise receiver based on the IEEE802.11P agreement, just can improve the ability of antagonism time selectivity and frequency selective fading, thereby improve the irrelevance of short training sequence and long training sequence, improve the precision of system synchronization.
Description of drawings
Fig. 1 is the frame assumption diagram of IEEE802.11p;
Fig. 2 is the flow chart that the present invention improves the embodiment of the method for the synchronous accuracy of high-speed moving OFDM system;
Fig. 3 is the available pattern diagram that increases the weight of during preemphasis in Fig. 2;
Fig. 4 is the particular flow sheet of simultaneous operation in Fig. 2.
Embodiment
The present invention is described in detail below in conjunction with drawings and Examples.
Fig. 1 is the frame assumption diagram of IEEE802.11p, Fig. 2 is the flow chart that the present invention improves the embodiment of the method for the synchronous accuracy of high-speed moving OFDM system, Fig. 3 is the available pattern diagram that increases the weight of during preemphasis in Fig. 2, and as shown in Figure 2, the synchronous method of the present embodiment comprises:
Stipulate according to WLAN (wireless local area network) (IEEE802.11a/p) agreement based on the frame structure that the OFDM System of WLAN of IEEE802.11p adopts; be its frame structure as shown in Figure 1; wherein front 10 symbols (symbol) are short training sequences; be used for thick synchronous; and two of back symbol is long training sequence; be used for channel estimating and thin frequency deviation estimation, GI2 is the protection time slot.
In this step, be that the short training sequence in frame structure shown in Figure 1 is carried out preemphasis.Due to after agreement decides, the numerical value of short training sequence is constant, by short training sequence is carried out preemphasis, be exactly namely to improve the amplitude of short training sequence to the preemphasis of short training sequence, resist time selectivity and frequency selective fading in the fast moving process, thus carry out synchronously can be more accurate.
In concrete the application, the following mode of employing is carried out preemphasis with the amplitude of short training sequence:
X(d)=R(d)+P(d)*R(d)
Wherein, X (d) is the short training sequence after preemphasis, and R (d) is the short training sequence of protocol of wireless local area network regulation, P (d)=a*Mod (d), and the increase the weight of pattern of Mod (d) for selecting, d=0 ... L-1; L ..., L+L-1; L+8*L ..., L+9*L-1, L are the bit number that single short training sequence comprises.A is the amplitude of preemphasis, is in linear input range in order to guarantee radio-frequency power amplifier always, need to reasonably design preferred 0≤a ﹤ 1 for the amplitude that increases the weight of of short training sequence.
The mathematic(al) representation of Mod (d) can for following pattern [1 ..., 1; 0 ..., 0; 1 ..., 1; 0 ..., 0], also can be any one pattern shown in Figure 3.
Increase the weight of to increase the energy of signal due to short training sequence, and the energy of increase signal can resist time selectivity and frequency selective fading; And short training sequence increases the weight of, and long training sequence does not increase the weight of, and can increase the irrelevance of length training sequence, produces the trailing edge edge of steeper, and therefore synchronous location is convenient, thereby can obtain relatively accurate sync bit.
Fig. 4 is the particular flow sheet of simultaneous operation in Fig. 2, and as shown in Figure 4, in concrete the application, the synchronizing process of this step comprises: thick synchronizing process and thin synchronizing process namely comprise:
Utilize the repetition short training sequence of 10 preemphasis to determine thick synchronous position, namely utilize carry out after in the frame structure of IEEE802.11p, front 10 symbols increase the weight of thick synchronous, complete thick synchronous after, due to the sync bit inaccuracy of obtaining, therefore, also need carefully synchronously the sync bit of ofdm system further to be proofreaied and correct, namely utilize 2 repetition long training sequences to calculate, constantly adjust the position of sliding window and determine thin synchronous position; By judging whether sync bit is accurate, if also inaccurate, continue to utilize 2 to repeat long training sequence calculating, determine thin synchronous position, if reach accurate requirement, can stop cyclic search and calculate, determine sync bit, namely obtain sync bit more accurately.
It is the ofdm system synchronous method of 201210509727.3 Chinese patent application that above-mentioned simultaneous operation adopts first thick synchronous thin synchronous method again can adopt application number.In actual applications, the simultaneous operation of above-mentioned steps 102 also can adopt in prior art other to utilize short sequence and long sequence to carry out synchronous method, and the present invention is not restricted at this.
The present invention is by carrying out preemphasis with the short training sequence in the protocol of wireless local area network frame structure, make ofdm system can not revise receiver based on the IEEE802.11P agreement, just can improve the ability of antagonism time selectivity and frequency selective fading, thereby improve the irrelevance of short training sequence and long training sequence, improve the precision of system synchronization.
It should be noted that at last: above embodiment is only in order to technical scheme of the present invention to be described but not be limited, although with reference to preferred embodiment, the present invention is had been described in detail, those of ordinary skill in the art is to be understood that: it still can be modified or be equal to replacement technical scheme of the present invention, and these modifications or be equal to replacement and also can not make amended technical scheme break away from the spirit and scope of technical solution of the present invention.
Claims (4)
1. a method that improves the synchronous accuracy of high-speed moving OFDM system, is characterized in that, comprising:
Short training sequence in the protocol of wireless local area network frame structure is carried out preemphasis;
Determine sync bit according to long training sequence in the short training sequence after preemphasis and protocol of wireless local area network frame structure.
2. method according to claim 1, is characterized in that, the short training sequence in the protocol of wireless local area network frame structure is carried out preemphasis, is specially:
The following mode that adopts is carried out preemphasis with the amplitude of short training sequence:
X(d)=R(d)+P(d)*R(d)
Wherein, X (d) is the short training sequence after preemphasis, and R (d) is the short training sequence of protocol of wireless local area network regulation, P (d)=a*Mod (d), and a is the amplitude of preemphasis, the increase the weight of pattern of Mod (d) for selecting, d=0 ... L-1; L ..., L+L-1; L+8*L ..., L+9*L-1, L are the bit number that single short training sequence comprises.
3. method according to claim 2, is characterized in that, the default amplitude a that increases the weight of satisfies: 0≤a ﹤ 1.
4. the described method of any one according to claim 1～3, is characterized in that, determines sync bit according to long training sequence in the short training sequence after preemphasis and protocol of wireless local area network frame structure, comprising:
Utilize the short training sequence of the preemphasis of a plurality of repetitions to determine thick synchronous position;
From thick sync bit, utilize the short training sequence of preemphasis to carry out carefully synchronizeing with the irrelevance of long training sequence, obtain thin sync bit.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105451362A (en) * | 2014-09-02 | 2016-03-30 | 电信科学技术研究院 | Adhoc network data transmission method and device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1812387A (en) * | 2005-01-28 | 2006-08-02 | 北京大学 | Orthogonal frequency division multiplexing communication method using prefix and suffix signals |
| CN101286794A (en) * | 2008-03-05 | 2008-10-15 | 中科院嘉兴中心微系统所分中心 | Frame synchronizing device applied in wireless sensor network |
| CN101883068A (en) * | 2009-05-09 | 2010-11-10 | 电子科技大学中山学院 | Superimposed training sequence time thickness synchronization method |
| CN102801684A (en) * | 2012-08-23 | 2012-11-28 | 中国航天科技集团公司第九研究院第七七一研究所 | Lead code pre-emphasis method of OFDM (Orthogonal Frequency Division Multiplexing) transceiver |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1812387A (en) * | 2005-01-28 | 2006-08-02 | 北京大学 | Orthogonal frequency division multiplexing communication method using prefix and suffix signals |
| CN101286794A (en) * | 2008-03-05 | 2008-10-15 | 中科院嘉兴中心微系统所分中心 | Frame synchronizing device applied in wireless sensor network |
| CN101883068A (en) * | 2009-05-09 | 2010-11-10 | 电子科技大学中山学院 | Superimposed training sequence time thickness synchronization method |
| CN102801684A (en) * | 2012-08-23 | 2012-11-28 | 中国航天科技集团公司第九研究院第七七一研究所 | Lead code pre-emphasis method of OFDM (Orthogonal Frequency Division Multiplexing) transceiver |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105451362A (en) * | 2014-09-02 | 2016-03-30 | 电信科学技术研究院 | Adhoc network data transmission method and device |
| CN105451362B (en) * | 2014-09-02 | 2019-07-19 | 电信科学技术研究院 | The data transmission method for uplink and device of ad hoc network |
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