CN110519861A - A kind of accidental access method based on time auxiliary - Google Patents
A kind of accidental access method based on time auxiliary Download PDFInfo
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- CN110519861A CN110519861A CN201910703215.2A CN201910703215A CN110519861A CN 110519861 A CN110519861 A CN 110519861A CN 201910703215 A CN201910703215 A CN 201910703215A CN 110519861 A CN110519861 A CN 110519861A
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- broadcast frame
- timing advance
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- 238000000034 method Methods 0.000 title claims abstract description 33
- 230000001360 synchronised effect Effects 0.000 claims abstract description 8
- 238000001514 detection method Methods 0.000 claims description 3
- 238000012546 transfer Methods 0.000 claims description 2
- 238000004891 communication Methods 0.000 abstract description 16
- 239000000284 extract Substances 0.000 abstract description 2
- 230000005540 biological transmission Effects 0.000 description 10
- 238000010586 diagram Methods 0.000 description 4
- 238000010295 mobile communication Methods 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 125000004122 cyclic group Chemical group 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000010267 cellular communication Effects 0.000 description 1
- 239000013256 coordination polymer Substances 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
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- 230000000750 progressive effect Effects 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/18502—Airborne stations
- H04B7/18504—Aircraft used as relay or high altitude atmospheric platform
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18517—Transmission equipment in earth stations
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/001—Synchronization between nodes
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/004—Synchronisation arrangements compensating for timing error of reception due to propagation delay
- H04W56/0045—Synchronisation arrangements compensating for timing error of reception due to propagation delay compensating for timing error by altering transmission time
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access
- H04W74/08—Non-scheduled access, e.g. ALOHA
- H04W74/0833—Random access procedures, e.g. with 4-step access
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Astronomy & Astrophysics (AREA)
- Aviation & Aerospace Engineering (AREA)
- General Physics & Mathematics (AREA)
- Radio Relay Systems (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
The invention discloses a kind of accidental access methods based on time auxiliary, belong to satellite communication field.This method assisted carrying out the time synchronization between gateway station and terminal based on the time；The local sending instant T0 information of downlink broadcast frame is filled into downlink broadcast frame by gateway station；Terminal receives the downlink broadcast frame after satellite forwards, and extracts T0, records the local reception moment T1 of downlink broadcast frame；The Timing Advance that terminal calculates random access is TA=2 (T1-T0)；Terminal sends uplink random to satellite in a manner of timing advance and accesses sequence, to realize the uplink synchronous between each terminal of access phase.Channel overhead is small in satellite communication system random access procedure, the low advantage of complexity.
Description
Technical field
The invention belongs to satellite communication fields, and in particular to a kind of accidental access method based on time auxiliary.
Technical background
The communication technology is constantly progressive, and satellite mobile communication has the characteristics that much to be better than terrestrial communication networks, just widely
Cause the concern of industry, it is huge that most companies and correspondence entity all think that the fusion of satellite and ground network infrastructure has
Market potential.Satellite provides wireless access and can help to promote do not servicing or owing service area's release communication service, to make up ground
The covering vacancy of torus network is that user equipment or mobile platform (such as automobile, aircraft, steamer, high-speed rail etc.) provide service continuously
Property enhances reliability.
Satellite includes Low Earth Orbit (LEO), Medium-Earth Orbit (MEO), geostationary orbit (GEO) or highly elliptical orbit
(HEO) aerospace craft in.LEO satellite operates on the track apart from ground 500km~1500km, and the rail of GEO satellite
Track pitch ground is more up to 36000km, and when satellite antenna angle of declination is smaller, terminal can also be considerably beyond this at a distance from satellite
A numerical value.The round-trip delay that satellite transmission is generally indicated with absolute RTT (Round-Trip Time) and opposite RTT, wherein absolutely
Is referred to RTT, opposite RTT is referred in satellite coverage signal two-way time needed for satellite and terminal room transmission
The maximum round trip time and minimum two-way time difference.As shown in Figure 1, in a wave beam cell, the end nearest apart from satellite
The public time delay having in the smallest propagation delay time and wave beam cell is held, the terminal farthest apart from satellite has maximum biography
Sowing time prolongs.For LEO satellite, typical absolutely RTT can achieve 40ms or so, and opposite RTT reaches 4ms or so.With
Unlike mobile communication system based on ground infrastructure, farther out, propagation delay time is larger on satellite distance ground.Due to satellite
The region of single wave cover is far longer than a cell range in ground based cellular communication system, satellite mobile communication system phase
Have the characteristics that transmission time delay difference is big to ground mobile communication system.
In satellite communication system, most important problem is to maintain the orthogonality of each terminal uplink, that is, sends
The frequency and time synchronization of signal.Consistent with GCS Ground Communication System, in satellite communication system, random access procedure referred at end
Before end is communicated with network, terminal adjusts the transmission frame timing and the alignment of network uplink frame of itself, establishes uplink synchronous
Process.The excessive time overhead that will increase terminal random access procedure of propagation delay time.With LTE system uplink PRACH (Physical
Random Access Channel, Physical Random Access Channel) for, as shown in Fig. 2, its time overhead includes leading
Preamble and protection interval (are denoted as TGT), when wherein Preamble includes CP (Cyclic Prefix, the cyclic prefix) of OFDM
Between (be denoted as TCP), ZC sequence time (be denoted as TSEQ).As shown in Fig. 2, needing to meet following relationship according to existing design criteria:
TCP>RTT+τd, TSEQ>RTT+τd, TGT>RTT
Wherein, τdIt is the extension of channel maximum delay.As can be seen that even if not considering τd, the totality of Physical Random Access Channel
Time overhead TRACHAlso 3 times of RTT are at least reserved, either using absolute RTT or opposite RTT, random access procedure
Require very big physical channel expense.
Summary of the invention
In order to solve the problems, such as that random access procedure bring physical channel expense is excessive in satellite communication system, the present invention
Propose a kind of accidental access method based on time auxiliary.
The invention proposes a kind of accidental access methods based on time auxiliary, pass through satellite link suitable for ground based terminal
The scene communicated, as shown in Figure 1.Each wave beam of satellite forms a wave beam cell on ground, the end in wave beam cell
End is communicated by satellite with gateway station.This method passes through following steps and realizes: gateway station and terminal be based on the time assist into
The synchronization of row local zone time；The local sending instant T0 information of downlink broadcast frame is filled into downlink broadcast frame by gateway station；Eventually
End receives the downlink broadcast frame after satellite forwards, and extracts T0, records the local reception moment T1 of downlink broadcast frame；Terminal
The Timing Advance for calculating random access is TA=2 (T1-T0)；Terminal in a manner of timing advance to satellite send uplink with
Machine accesses sequence, to realize the uplink synchronous between each terminal of access phase.
Further, the gateway station assists carrying out the synchronous method of local zone time with terminal based on the time are as follows: navigation
Time service, time calibration in network or detection frame comparison.
The present invention it is a kind of based on the time auxiliary accidental access method, relative to existing technology have it is below the utility model has the advantages that
(1) Timing Advance for assisting obtaining random access the present invention is based on the time, caused by reducing big propagation delay
The expense of random access channel.
(2) the present invention is based on the modes of time auxiliary to belong to open loop approach, on the basis of realizing that local zone time is synchronous, letter
Interaction broadcast frame sending instant information is only needed between Guan Zhanyu terminal, implementation complexity is low.
(3) the method for the present invention can be used the modes such as navigation time service, time calibration in network, detection frame comparison and obtain time synchronization, from
And Timing Advance is calculated, it is applicable not only to satellite communication field, and be suitable for the biggish communication of other propagation delays
Scene, engineer application range are wide.
Detailed description of the invention
Fig. 1 is satellite communication system propagation delay time schematic diagram.
Fig. 2 is LTE uplink PRACH signal schematic representation.
Fig. 3 is that the present invention is based on the accidental access method embodiment schematic diagrams of time auxiliary.
Fig. 4 is absolute time delay compensation way schematic diagram.
Fig. 5 is relative time delay compensation way schematic diagram.
Specific embodiment
Invention will be further explained below with reference to the drawings and examples..
The invention proposes a kind of accidental access methods based on time auxiliary, and navigation time service, time calibration in network, spy can be used
It surveys the modes such as frame comparison and obtains time synchronization, Timing Advance is calculated on this basis, and send out in a manner of timing advance
Random access sequence is sent, random access is started.The method of the present invention is suitable for satellite communication field.As shown in figure 3, with using navigation
For time service mode, the step of the method for the present invention, is as follows:
Step 1: gateway station and terminal are based respectively on navigation time service and update local zone time, thus realize gateway station and terminal it
Between local zone time it is synchronous；
Step 2: gateway station sends downlink broadcast, and the downlink broadcast obtained based on navigation time service is filled in downlink broadcast frame
Frame sending instant TDOWN；
Step 3: after terminal receives downlink broadcast frame, parsing the T for including in downlink broadcast frameDOWNInformation, and record
Downlink broadcast frame local reception moment T based on navigation time serviceUE；
Step 4: terminal is according to TDOWNAnd TUECalculate downlink transfer time delay TDELAY:
TDELAY=TUE-TDOWN
Terminal calculates Timing Advance TA:
TA=2TDELAY
Step 5: terminal sends random access sequence according to the Timing Advance being calculated in a manner of timing advance,
Start random access.
The method of the present invention can use absolute time delay compensation way after obtaining Timing Advance.As shown in figure 4, in wave beam
In cell, terminal 1 is nearest apart from satellite, so by the method for the invention, when its propagation delay is exactly the minimum of wave beam cell
Prolong, its propagation delay is TDELAY,1, and the propagation delay of terminal 2 is TDELAY,2.It is carried out at random in the mode based on timing advance
When accessing sequence transmission, the Timing Advance of terminal 1 is TA,1=2TDELAY,1；The Timing Advance of terminal 2 is TA,2=
2TDELAY,2.Then, the random access sequence of terminal 1 and terminal 2 reaches the gateway station time difference not by the big propagation on communication link
The influence of time delay.
The method of the present invention is equally applicable to relative time delay compensation way.As shown in figure 5, terminal 1 is nearest apart from satellite, it
Propagation delay is exactly the public time delay of wave beam cell, its counterpropagate time delay is TDELAY,1=0ms；The counterpropagate of terminal 2
Time delay is TDELAY,2.When the mode based on timing advance carries out random access sequence transmission, by adding in downlink broadcast frame
Add public Delay, it is T that terminal 1, which can get Timing Advance,A,1=2TDELAY,1=0ms；Terminal 2 can get Timing Advance
For TA,2=2TDELAY,2。
According to the design rule of traditional random access sequence, in order to guarantee the random access sequence of terminal in wave beam cell
It all distinguishes, and the data of random access frame will not trail to next subframe, cause intersymbol interference, random access sequence
CP length TCPWith GT length TGTIt requires to be more than terminal room maximum round trip transmission time delay difference in cell, for satellite communication system,
Terminal room round trip transmission delay difference reaches as high as several milliseconds in cell.In the method for the present invention, terminal is sending random access sequence
The transmission time delay difference of each terminal room estimate and supplemented by way of timing advance before, connect at random
Enter the CP length T of sequenceCPWith GT length TGTDesign no longer need to consider transmission time delay difference, maximum can reduce by several milliseconds of length
Random access channel expense.
The embodiment of the present invention has been described in detail above, and specific embodiment used herein carries out the present invention
It illustrates, the above description of the embodiments is only used to help understand the method and apparatus of the present invention；Meanwhile for the one of this field
As technical staff, according to the thought of the present invention, there will be changes in the specific implementation manner and application range, to sum up institute
It states, the contents of this specification are not to be construed as limiting the invention.
Claims (3)
1. a kind of accidental access method based on time auxiliary, this method are as follows: gateway station and terminal are based on time auxiliary and carry out this
The synchronization of ground time；The local sending instant T0 information of downlink broadcast frame is filled into downlink broadcast frame by gateway station；Terminal connects
The downlink broadcast frame after satellite forwards is received, T0 is extracted, records the local reception moment T1 of downlink broadcast frame；Terminal calculates
The Timing Advance of random access is TA=2 (T1-T0) out；Terminal sends uplink random to satellite in a manner of timing advance and connects
Enter sequence, to realize the uplink synchronous between each terminal of access phase.
2. a kind of accidental access method based on time auxiliary as described in claim 1, this method method particularly includes:
Step 1: gateway station and terminal are based respectively on navigation time service and update local zone time, to realize between gateway station and terminal
Local zone time is synchronous；
Step 2: gateway station sends downlink broadcast, sends out in downlink broadcast frame filled with the downlink broadcast frame obtained based on navigation time service
Send moment TDOWN；
Step 3: after terminal receives downlink broadcast frame, parsing the T for including in downlink broadcast frameDOWNInformation, and record and be based on leading
The downlink broadcast frame local reception moment T of boat time serviceUE；
Step 4: terminal is according to TDOWNAnd TUECalculate downlink transfer time delay TDELAY:
TDELAY=TUE-TDOWN
Terminal calculates Timing Advance TA:
TA=2TDELAY
Step 5: terminal sends random access sequence according to the Timing Advance being calculated in a manner of timing advance, starts
Random access.
3. a kind of accidental access method based on time auxiliary as described in claim 1, it is characterised in that the gateway station and
The method that terminal assists carrying out the synchronization of local zone time based on the time are as follows: navigation time service, time calibration in network or detection frame comparison.
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| CN201910703215.2A CN110519861A (en) | 2019-07-31 | 2019-07-31 | A kind of accidental access method based on time auxiliary |
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| CN201910703215.2A CN110519861A (en) | 2019-07-31 | 2019-07-31 | A kind of accidental access method based on time auxiliary |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112260745A (en) * | 2020-10-15 | 2021-01-22 | 重庆金美通信有限责任公司 | Rapid access method for low-earth-orbit satellite system |
| CN112636813A (en) * | 2020-12-28 | 2021-04-09 | 四川安迪科技实业有限公司 | Long-time uncertain login method and device for TDMA satellite communication system and storage medium |
| WO2021129633A1 (en) * | 2019-12-26 | 2021-07-01 | 海能达通信股份有限公司 | Uplink data synchronization method and device |
| CN113382467A (en) * | 2021-06-08 | 2021-09-10 | 东南大学 | Uplink sending timing adjusting method |
| WO2021232412A1 (en) * | 2020-05-22 | 2021-11-25 | 株式会社Ntt都科摩 | Terminal and method executed by terminal |
| WO2021253178A1 (en) * | 2020-06-15 | 2021-12-23 | 北京小米移动软件有限公司 | Random access method, random access device, and storage medium |
| CN114071691A (en) * | 2020-08-07 | 2022-02-18 | 北京佰才邦技术股份有限公司 | Random access response detection method, device, terminal and base station side equipment |
| CN114567923A (en) * | 2020-11-27 | 2022-05-31 | 北京九天微星科技发展有限公司 | Uplink synchronization method in satellite communication system |
| CN115039354A (en) * | 2021-01-05 | 2022-09-09 | 北京小米移动软件有限公司 | Access method, auxiliary information processing method and device, equipment and storage medium |
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021129633A1 (en) * | 2019-12-26 | 2021-07-01 | 海能达通信股份有限公司 | Uplink data synchronization method and device |
| WO2021232412A1 (en) * | 2020-05-22 | 2021-11-25 | 株式会社Ntt都科摩 | Terminal and method executed by terminal |
| CN114080856A (en) * | 2020-06-15 | 2022-02-22 | 北京小米移动软件有限公司 | Random access method, random access device and storage medium |
| CN114080856B (en) * | 2020-06-15 | 2024-03-01 | 北京小米移动软件有限公司 | Random access method, random access device and storage medium |
| WO2021253178A1 (en) * | 2020-06-15 | 2021-12-23 | 北京小米移动软件有限公司 | Random access method, random access device, and storage medium |
| CN114071691A (en) * | 2020-08-07 | 2022-02-18 | 北京佰才邦技术股份有限公司 | Random access response detection method, device, terminal and base station side equipment |
| CN112260745A (en) * | 2020-10-15 | 2021-01-22 | 重庆金美通信有限责任公司 | Rapid access method for low-earth-orbit satellite system |
| CN114567923A (en) * | 2020-11-27 | 2022-05-31 | 北京九天微星科技发展有限公司 | Uplink synchronization method in satellite communication system |
| CN112636813A (en) * | 2020-12-28 | 2021-04-09 | 四川安迪科技实业有限公司 | Long-time uncertain login method and device for TDMA satellite communication system and storage medium |
| CN115039354A (en) * | 2021-01-05 | 2022-09-09 | 北京小米移动软件有限公司 | Access method, auxiliary information processing method and device, equipment and storage medium |
| CN115039354B (en) * | 2021-01-05 | 2024-02-13 | 北京小米移动软件有限公司 | Access method, auxiliary information processing method, device, equipment and storage medium |
| CN113382467B (en) * | 2021-06-08 | 2022-04-15 | 东南大学 | Uplink sending timing adjusting method |
| CN113382467A (en) * | 2021-06-08 | 2021-09-10 | 东南大学 | Uplink sending timing adjusting method |
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Application publication date: 20191129 |