CN102076058A

CN102076058A - Random access method under large time delay and terminal

Info

Publication number: CN102076058A
Application number: CN2011100446466A
Authority: CN
Inventors: 周海军; 康绍莉; 王映民
Original assignee: China Academy of Telecommunications Technology CATT
Current assignee: China Academy of Telecommunications Technology CATT; Datang Mobile Communications Equipment Co Ltd
Priority date: 2011-02-23
Filing date: 2011-02-23
Publication date: 2011-05-25
Anticipated expiration: 2031-02-23
Also published as: CN102076058B

Abstract

The invention discloses a random access method under large time delay and a terminal. The method comprises the following steps that: the terminal determines the transmission time of synchronization code uplink (SYNC_UL) according to two-way time delay round trip time (RTT) between the terminal and a base station, wherein the RTT is acquired by the terminal through system broadcasting or is a predefined value; and the terminal selects an uplink pilot channel (UpPCH) corresponding to the SYNC_UL, transmits the SYNC_UL on the selected UpPCH and executes a random access process. By the method and the terminal, waste of system resources is avoided; and accurate synchronization between the base station and the terminal is realized.

Description

Accidental access method under a kind of long time delay and terminal

Technical field

The present invention relates to wireless communication technology field, relate in particular to accidental access method and terminal under a kind of long time delay.

Background technology

TD-SCDMA (Time Division-Synchronous Code Division Multiple Access; TD SDMA) subframe structure of system as shown in Figure 1; this subframe comprises DwPTS (the Downlink Pilot Time Slot that is used for down-going synchronous; down link pilot timeslot), be used to prevent the protection time slot Main GP that disturbs between the uplink and downlink signals, the UpPTS (Downlink Pilot TimeSlot, down link pilot timeslot) that is used for uplink synchronous and the conventional time slot TS0～TS6 that is used for transmitting user data.

In the TD-SCDMA system,,, as shown in Figure 2, mainly carry out following steps for the UE side based on the random access procedure of above-mentioned subframe structure:

Step S201, the count value that the signature retransmission counter is set is M, and the signature transmitting power is set;

Step S202, given ASC (Access Service Classes from UE, service class) corresponding available UpPCH (Uplink Pilot Channel, ascending pilot channel) select one in the subchannel at random, must to satisfy each available selected probability of UpPCH subchannel identical for used random function during selection;

Step S203, at the UpPTS time slot, on the UpPCH subchannel of selecting, adopt the signature transmitting power that is provided with to send the request that inserts at random, this inserts request at random and carries SYNC UL (the Synchronization Code Uplink corresponding with the UpPCH subchannel of selecting, uplink synchronous code), realize the signature emission;

Step S204, signature emission back UE listens to relevant FPACH (the Fast PhysicalAccess Channel of UpPCH subchannel, the rapid physical Acquisition Indicator Channel), the DwPTS time slot from subsequently the individual subframe of WT (Wait Time, stand-by period) obtains accidental access response.

UE will read the FPACH relevant with launching the UpPCH subchannel from the subframe that satisfies following relationship:

SFN′mod?L _i＝n _RACHi，n _RACHi＝0，...，N _RACHi-1

Wherein SFN ' is a subframe numbers, L _iBe n _RACHiThe length of individual RACH (Random Access Channel, Random Access Channel) message, n _RACHiBe the numbering of RACH message, N _RACHiBe the maximum numbering of RACH message, wherein the length of RACH message and numbering are indicated to UE by network side.

Whether step S205 determines to listen within the scheduled time to get accidental access response, promptly whether detects the effective response of network side, if not, and execution in step S206, otherwise execution in step S207.

Step S206, if do not detect effective response within the scheduled time, the count value of signature retransmission counter subtracts 1.Whether the count value of judging the signature retransmission counter still greater than 0, if, return execution in step S202, otherwise execution in step S207.

Step S207 reports once access failure at random to MAC (Media Access Control, medium access control) layer.

Step S208 determines to listen within the scheduled time to get accidental access response, promptly detects the effective response of network side, then is arranged on concrete time and the transmitted power level value that the UpPTS time slot sends RACH message according to accidental access response;

Step S209, after the subframe of carrying Signature Confirmation promptly receives the subframe of accidental access response, two subframes of being separated by, the relevant PRACH (Physical Random Access Channel, Physical Random Access Channel) of FPACH that is arranged on of S208 goes up and sends RACH message set by step.If the length of RACH message is greater than 1, and the subframe numbers of Signature Confirmation is odd number, and UE need wait for a subframe again.

In the TD-SCDMA system,, for network side, carry out random access procedure, mainly carry out following steps based on above-mentioned subframe structure:

1) base station node B only in satisfying the subframe of following relationship, is launched accidental access response on the FPACH relevant with UpPCH:

SFN′mod?L _i＝n _RACHi，n _RACHi＝0，...，N _RACHi-1

Wherein SFN ' is a subframe numbers, L _iBe n _RACHiThe length of individual RACH message, n _RACHiBe the numbering of RACH message, N _RACHiMaximum numbering for RACH message.

After NodeB receives the request of access at random of UE at the UpPCH time slot, determine that its SYNC_UL that carries is for effectively signing, from the connect time deviation of reference time in first footpath of receiving of UpPCH measurement, UE is set sends the concrete time of RACH message, and on the relevant FPACH of UpPCH, send accidental access response at the UpPTS time slot.

2) before NodeB can not respond and set a quantity WT subframe, the request of access at random that UE sends at the UpPCH time slot.

Because UE inserts at random, conflict most possibly occurs in the UpPCH time slot that sends SYNC_UL, and the probability that RACH RU (RACH Resource Unit) clashes reduces greatly, and can guarantee that RACH RU can handle with conventional business is common in same UL time slot.

When the conflict possibility is big, or in relatively poor communication environments, NodeB can not receive SYNC_UL, or does not launch accidental access response at FPACH after receiving.In this case, UE just can not get any response of NodeB.Therefore UE must remeasure after a random request postpones and adjust SYNC_UL in UpPCH time slot launch time and transmitting power, and sends a SYNC_UL.And when each emission (or repeating transmission), UE can select the SYNC_UL sequence again at random.

Existing system thinks that propagation delay is delicate level, so the subframe of UE and network terminal is alignd in time, network receives the subframe of the subframe UE transmission just SYNC_UL of SYNC_UL.And in satellite communication system; UE to the propagation delay of satellite from tens to milliseconds up to a hundred; if directly adopt the frame structure in the TD-SCDMA system; as shown in Figure 3; protection value at interval is 0.075ms+N*5ms, needs protection between DwPTS and UpPTS to be greater than at interval and equals the two-way propagation time delay, under the condition of fixed statellite; this value is greater than 200ms.Will be arranged by vacant the above time of 200ms like this in each subframe, may bring a large amount of wasting of resources or can't operate as normal, system effectiveness is lower.

In satellite communication system,, can bring following problem if carry out synchronously and random access procedure based on the TD-SCDMA frame structure:

1) time delay is judged according to path loss by present TD-SCDMA system, but the calculating of path loss can be subjected to the influence of a plurality of factors, comprise loss, atmospheric refraction, antenna direction tracking error, ionospheric scintillation etc., consider that more certain error of calculation is easy to the above path loss of 2dB and changes, propagation delay evaluated error more than the 31ms will be arranged for geosynchronous satellite.

Base station (satellite) is to determine SYNC_UL at the concrete delivery time of UpPTS according to UE to the propagation delay of satellite, so that base station (satellite) receives SYNC_UL at UpPTS.And if for the frame structure of 5ms, judge time delay if also adopt path loss, the propagation delay evaluated error is excessive, may cause actual SYNC_UL arrive base station (satellite) the time be engraved in any position of 5ms frame, like this uplink service time slot is brought interference, base station (satellite) also may lose SYNC_UL.

Protect the setting of time slot also may attract the interference of uplink and downlink signals simultaneously.

2) One Way Delay may be more than several subframes in the delay inequality of the different UEs of ms more than 100, if so also determined the FPACH of receiving random access response according to former processing method, by existing standard is to receive FPACH in 4 subframes subsequently, UE can't receive accidental access response on oneself the FPACH so, but also the FPACH that might by mistake receive other UE goes up accidental access response, thereby cause the collision of PRACH, or incorrect other uplink service time slots are produced of the transmitting time of PRACH disturbed.

The above-mentioned system that either way can cause can't operate as normal.

Summary of the invention

The invention provides accidental access method and terminal under a kind of long time delay, in order to solve in the prior art based on the serious problem of system resource waste in the TD-SCDMA system.

The invention provides the accidental access method under a kind of long time delay, comprising:

Two-way time delay RTT between terminal basis and base station, definite time that sends uplink synchronous code SYNC_UL, described terminal obtains described RTT by system broadcasts, or described RTT is pre-defined value;

Terminal is selected the ascending pilot channel UpPCH corresponding with SYNC_UL, sends SYNC_UL on the UpPCH that selects, and carries out random access procedure.

Preferably, FDD is adopted in terminal and base station in this method, carry out transmitting uplink data based on sub-frame of uplink, simultaneously carry out downlink data transmission based on descending sub frame, described sub-frame of uplink comprises the uplink pilot time slot UpPTS that is used for uplink synchronous and is used to transmit the uplink service time slot of uplink user data, and described descending sub frame comprises the down link pilot timeslot DwPTS that is used for down-going synchronous and with the downlink business time slot that transmits down user data.

Preferably, the length of described sub-frame of uplink and descending sub frame is 5ms, and sub-frame of uplink comprises 1 UpPTS and 7 uplink service time slots, and descending sub frame comprises 1 DwPTS and 7 downlink business time slots.

Preferably, terminal based on the sub-frame of uplink starting point shift to an earlier date RTT than descending sub frame starting point, the base station based on sub-frame of uplink and the definitely alignment in time of the starting point of descending sub frame; And sub-frame of uplink is identical with the subframe lengths T of descending sub frame, terminal based on the sub-frame of uplink starting point than the base station based on the sub-frame of uplink starting point shift to an earlier date RTT/2.

Preferably, terminal specifically comprised according to the time that described RTT determines to send uplink synchronous code SYNC_UL:

Determine the leading current time starting point x transmission SYNC_UL of a descending sub frame afterwards, wherein:

X=(RTT-(time that the relative sub-frame of uplink starting point of the SYNC_UL of setting lags behind)) mod (T)

T is the subframe lengths of sub-frame of uplink and descending sub frame.

Preferably, terminal sends after the SYNC_UL, also comprises:

When terminal sends SYNC_UL and waits for RTT, in N descending sub frame of setting quantity subsequently, detect the timed message of whether receiving on the rapid physical Acquisition Indicator Channel FPACH;

When terminal is determined to receive timed message, according to the time deviation modified R TT in the timed message, and according to revised RTT adjustment sub-frame of uplink and descending sub frame starting point;

Adjust back terminal 2 or 3 sub-frame of uplink in interval after receiving timed message, on the corresponding Physical Random Access Channel PRACH of FPACH, send Random Access Channel RACH message.

Preferably, described N is 4, if the length of the RACH message that will send is greater than 1, and receives that the subframe numbers of the descending sub frame of timed message is an odd number, and 3 sub-frame of uplink send the RACH message at interval, otherwise 2 sub-frame of uplink send the RACH message at interval.

Preferably, terminal obtains described RTT by system broadcast message, specifically comprises:

Terminal obtains the center time delay according to the receiving system broadcast, and determines RTT according to described center time delay, and described center time delay is determined according to the distance between the center of base station and sub-district, place, base station.

Preferably, in this method, terminal determines that on absolute time a pair of sub-frame of uplink and the descending sub frame that satisfy following condition are considered as same subframe: the time range＜subframe lengths T of the leading descending sub frame of 0ms=＜sub-frame of uplink.

Preferably, terminal determines that the method for next sub-frame of uplink/descending sub frame is in this method:

Determine current sub-frame of uplink and the descending sub frame that is considered as same subframe, and determine that the sub-frame of uplink/descending sub frame after the same subframe is next sub-frame of uplink/descending sub frame.

Preferably, the division of sub-district makes the one way propagation delay inequality of all terminals in the same sub-district in subframe lengths T.

Preferably, it is surplus that the division of sub-district makes the one way propagation time delay of all terminals in the sub-district get T, and the terminal of remainder in T/2 be a sub-district, remainder at T/2 to the terminal between T in the another one sub-district.

Preferably, the division of sub-district is not more than the one way propagation delay inequality of all terminals in the sub-district and sends 1/2 of SYNC_UL permission jitter range.

Preferably, described transmission SYNC_UL allows the number of chips of jitter range by the Time Slot Occupancy that allows transmission SYNC_UL in the sub-frame of uplink, deducts the shared number of chips of SYNC_UL transmission and determines.

Preferably, the time slot that described permission sends SYNC_UL is UpPTS, or is 1 uplink service time slot after the UpPTS+UpPTS, or is 2 uplink service time slots after the UpPTS+UpPTS.

Preferably,, allow 1/2 of jitter range at SYNC_UL, realize that the one way propagation delay inequality of all terminals in the sub-district is not more than 1/2 of transmission SYNC_UL permission jitter range by the center time delay difference that makes neighbor cell in the microzonation timesharing.

The terminal that the present invention also provides the carrying out under a kind of long time delay to insert at random comprises:

The time-delay determining unit is used for according to the two-way time delay RTT between terminal and base station, determines to send the time of uplink synchronous code SYNC_UL, and described RTT obtains by system broadcasts, or described RTT is pre-defined value;

Access unit is used to select the ascending pilot channel UpPCH corresponding with SYNC_UL at random, sends SYNC_UL on the UpPCH that selects, and carries out random access procedure.

Preferably, each unit in the described terminal adopts FDD, carry out transmitting uplink data based on sub-frame of uplink, simultaneously carry out downlink data transmission based on descending sub frame, described sub-frame of uplink comprises the uplink pilot time slot UpPTS that is used for uplink synchronous and is used to transmit the uplink service time slot of uplink user data, and described descending sub frame comprises the down link pilot timeslot DwPTS that is used for down-going synchronous and with the downlink business time slot that transmits down user data.

Preferably, each unit in the described terminal based on the sub-frame of uplink starting point shift to an earlier date RTT than descending sub frame starting point, each unit in the described terminal based on the sub-frame of uplink starting point than the base station based on the sub-frame of uplink starting point shift to an earlier date RTT/2, the base station based on sub-frame of uplink and the definitely alignment in time of the starting point of descending sub frame, and sub-frame of uplink is identical with the subframe lengths T of descending sub frame.

Preferably, described time-delay determining unit specifically is used for determining the leading current time starting point x transmission SYNC_UL of a descending sub frame afterwards, wherein: x=(RTT-(time that the relative sub-frame of uplink starting point of the SYNC_UL of setting lags behind)) mod (T), T is the subframe lengths of sub-frame of uplink and descending sub frame.

Preferably, this terminal also comprises:

Detecting unit is used for when sending SYNC_UL and waiting for RTT, detects the timed message of whether receiving on the rapid physical Acquisition Indicator Channel FPACH in N descending sub frame of setting quantity subsequently;

Amending unit, when being used to determine to receive timed message, according to the time deviation modified R TT in the timed message, and according to revised RTT adjustment sub-frame of uplink and descending sub frame starting point;

Response unit is used to adjust back terminal 2 or 3 sub-frame of uplink in interval after receiving timed message, sends Random Access Channel RACH message on the corresponding Physical Random Access Channel PRACH of FPACH.

Preferably, described time-delay determining unit specifically is used for obtaining the center time delay according to the receiving system broadcast, and determines RTT according to described center time delay, and described center time delay is determined according to the distance between the center of base station and sub-district, place, base station.

Preferably, this terminal also comprises: same subframe determining unit is used to determine that in absolute time a pair of sub-frame of uplink and the descending sub frame that satisfy following condition are considered as same subframe: the time range＜subframe lengths T of the leading descending sub frame of 0ms=＜sub-frame of uplink.

Preferably, this terminal also comprises: next subframe determining unit is used for determining current sub-frame of uplink and the descending sub frame that is considered as same subframe, and determines that the sub-frame of uplink/descending sub frame after the same subframe is next sub-frame of uplink/descending sub frame.

Preferably, in the sub-district, terminal place the one way propagation delay inequality of all terminals in subframe lengths T.

Preferably, the one way propagation time delay of all terminals is got surplusly in the sub-district, described terminal place to T, and the terminal of remainder in T/2 be a sub-district, remainder at T/2 to the terminal between T in the another one sub-district.

Preferably, the one way propagation delay inequality of all terminals is not more than and sends 1/2 of SYNC_UL permission jitter range in the sub-district, described terminal place.

Utilize the method and the terminal that insert at random under the long time delay provided by the invention, have following beneficial effect: avoided resource waste is reached because time delay is estimated the up-downgoing data interference of inaccurate formation, realized the accurately synchronous of network side and terminal.

Description of drawings

Fig. 1 is the subframe structure schematic diagram of existing TD-SCDMA system;

Fig. 2 is existing terminal synchronizes and random access procedure flow chart;

Fig. 3 adopts the subframe structure schematic diagram of TD-SCDMA down for long time delay;

The descending sub frame structural representation that Fig. 4 adopts for the embodiment of the invention;

The sub-frame of uplink structural representation that Fig. 5 adopts for the embodiment of the invention;

Fig. 6 is the sequential relationship schematic diagram of base station and terminal room in the embodiment of the invention;

Fig. 7 is the accidental access method flow chart under the long time delay in the embodiment of the invention.

Embodiment

Below in conjunction with drawings and Examples accidental access method under the long time delay provided by the invention and terminal are explained in more detail.

Original TD-SCDMA system thinks that propagation delay is delicate level, so the ascending-descending subframes of terminal UE and base station align in time, the base station receives the subframe of the subframe UE transmission just SYNC_UL of SYNC_UL.(the one way propagation time delay of terminal to base station surpasses TDMA (TimeDivision Multiple Access and at long time delay; time division multiplexing) protection system at interval) under the situation; the TD-SCDMA system can cause SYNC_UL arrive the base station the time be engraved in any position of 5ms frame, upstream data is formed disturbs even cause system to work.

The invention provides the accidental access method under a kind of long time delay, comprise: the two-way time delay RTT between terminal basis and base station, determine to send the time of uplink synchronous code SYNC_UL, described terminal obtains described RTT by system broadcasts, or described RTT is pre-defined value; Terminal is selected the ascending pilot channel UpPCH corresponding with SYNC_UL, sends SYNC_UL on the UpPCH that selects, and carries out random access procedure.

Preferably, terminal obtains described RTT by system broadcast message, specifically comprise: terminal obtains the center time delay according to the receiving system broadcast, and determines RTT according to described center time delay, and described center time delay is determined according to the distance between the center of base station and sub-district, place, base station.

Preferably, FDD (Frequency DivisionDuplexing is adopted in terminal and base station in this method, Frequency Division Duplexing (FDD)), carry out transmitting uplink data based on sub-frame of uplink, simultaneously carry out downlink data transmission based on descending sub frame, described sub-frame of uplink comprises the uplink pilot time slot UpPTS that is used for uplink synchronous and is used to transmit the uplink service time slot of uplink user data, and described descending sub frame comprises the down link pilot timeslot DwPTS that is used for down-going synchronous and with the downlink business time slot that transmits down user data.

Preferably, terminal based on the sub-frame of uplink starting point than terminal based on the descending sub frame starting point shift to an earlier date RTT, the base station based on sub-frame of uplink and the base station based on descending sub frame starting point in time definitely the alignment; And sub-frame of uplink is identical with the subframe lengths T of descending sub frame, terminal based on the sub-frame of uplink starting point than the base station based on the sub-frame of uplink starting point shift to an earlier date RTT/2, like this, terminal based on the descending sub frame starting point than the base station based on the starting point hysteresis RTT/2 of descending sub frame.

At propagation delay in the TDD mode of TD-SCDM when big, problem that system resource waste is serious, so need to introduce the frame structure of FDD mode.In the embodiment of the invention under the long time delay environment; the frame structure of FDD mode is introduced in terminal and data communication; all time slots all are used for sending downlink data in the descending sub frame structure; all time slots all are used for sending upstream data in the sub-frame of uplink structure; realize duplex communication by frequency division multiplexing; therefore the subframe structure time slot that do not need protection; therefore do not need to estimate to protect time slot according to the time delay of terminal to base station; just avoided also under the TDD mode that to cause protecting time slot to be provided with greatly improper because of the time delay evaluated error, and the problem that causes uplink and downlink signals to disturb.Sequential relationship between the ascending-descending subframes of the ascending-descending subframes of terminal and network side can make the transceive data time of end side and network side understanding consistent simultaneously, has realized the data sync between terminal and base station.

As Fig. 4, shown in Figure 5, the length of sub-frame of uplink and descending sub frame is 5ms, and sub-frame of uplink comprises 1 UpPTS and 7 uplink service time slots (time slot 0～time slot 6), and descending sub frame comprises 1 DwPTS and 7 downlink business time slots (time slot 0～time slot 6).The effect of special time slot UpPTS is with the effect of UpPTS in the TDD mode, still be used in order to realize that uplink synchronous sends uplink synchronous code SYNC_UL, special time slot DwPTS still is used for sending downlink frequency pilot code, can consider to expand its code length to improve reliability or to be used for other demand.

Consider that from the angle of compatibility the FDD mode remains unchanged for the special time slot DwPTS of descending sub frame structure with respect to the subframe structure of TDD in the present embodiment; Special time slot UpPTS for the sub-frame of uplink structure remains unchanged, and the design of DwPTS at present can be directly used in the communication of long time delay such as satellite.

Embodiment 1

Think that in original system propagation delay is delicate level, so the ascending-descending subframes of terminal and base station aligns in time, network receives the subframe of the subframe terminal transmission just SYNC_UL of SYNC_UL.And in the communication system of long time delay, according to the data communications method under the long time delay provided by the present invention, this relation has been broken, provides the new mechanism of definition in the present embodiment, i.e. the frame structure of FDD mode.

The notion that in process such as access at random, needs to use next frame or two frames, same owing to terminal is no longer alignd on ascending-descending subframes with the base station, present embodiment is used some notions to the terminal random access procedure and is redefined, according to the needs of the relevant control of physical layer, to base station and terminal based on the ascending-descending subframes correlation timing do as giving a definition:

1) at the base station end, base station communication based on ascending-descending subframes be absolute alignment in time, as shown in Figure 6, according to the relation between network uplink sequential and the descending sequential of network, at the base station end, the starting point of sub-frame of uplink is alignd with the starting point of descending sub frame; For terminal, terminal based on the sub-frame of uplink starting point shift to an earlier date RTT than descending sub frame starting point, terminal based on the sub-frame of uplink starting point shift to an earlier date RTT/2 than the base station based on the sub-frame of uplink starting point, RTT is the two-way time delay between terminal and base station.When the terminal of diverse location and base station communication based on the starting point of ascending-descending subframes because different and different with the propagation delay between the base station.According to Fig. 6, the starting point of the ascending-descending subframes of UE1 is different from the starting point of the ascending-descending subframes of UE2.

2) for terminal, the same subframe between so-called ascending-descending subframes, do as giving a definition:

On absolute time, a pair of ascending-descending subframes that the time range of the leading descending sub frame of sub-frame of uplink satisfies following condition is called same subframe: the time range＜subframe lengths of the leading descending sub frame of 0ms=＜sub-frame of uplink (5ms).

3) for the definition of next subframe: on up direction, next sub-frame of uplink is a back sub-frame of uplink of sub-frame of uplink in the same subframe, and on down direction, next descending sub frame is back one a descending subframe of descending sub frame in the same subframe.

Terminal is determined the method for next sub-frame of uplink/descending sub frame in the embodiment of the invention, is equally applicable to determine that two or three wait setting quantity sub-frame of uplink/descending sub frame down.

When the terminal of diverse location and base station communication based on the starting point of ascending-descending subframes because different and different with the propagation delay between the base station.Preferably, the base station is with center time delay terminal in descending sub frame is broadcast to the sub-district of sub-district in the present embodiment, and the center time delay of described sub-district is determined according to the distance between the center of base station and sub-district, place, base station; Terminal when inserting at random with the center time delay of base station broadcast as RTT.Preferably, the base station is in first time slot broadcasting center time delay of subframe, like this base station can according to time of receiving center time delay and center time delay determine the base station based on the starting point of ascending-descending subframes, certainly, can also select other to set time slot broadcasting center time delay, so that terminal can calculate the ascending-descending subframes starting point of base station end, and adjust the starting point of the ascending-descending subframes of oneself according to the center time delay of broadcasting.

For satellite communication, as the satellite of base station longitude and latitude of living in is known, the coverage of each sub-district is known when plot planning, therefore by calculating the distance between satellite and each the center of housing estate position, just can accurately calculate the electromagnetic wave propagation time delay.

Preferably, because when initial, in the sub-district terminal with the center time delay of base station broadcast as RTT, therefore the RTT of terminal is identical in the same sub-district, the RTT of different districts is different, little in order to guarantee terminal is thought in the sub-district RTT and actual RTT error, preferably, the division of sub-district makes the one way propagation delay inequality of all terminals in the same sub-district in subframe lengths T in the present embodiment.Simultaneously, the one way propagation delay inequality of terminal can also be avoided the collision of PRACH in the control sub-district in subframe lengths T.

In the present embodiment in order further to reduce RTT and the actual RTT error of thinking when terminal initial inserts, the division of sub-district makes the one way propagation time delay of all terminals in the sub-district get surplus to subframe lengths T, (0=＜remainder＜T/2), (terminal between T/2=＜remainder＜T) is in the another one sub-district to T at T/2 for remainder a sub-district for the terminal of remainder in T/2.

The embodiment of the invention realizes that the one way propagation delay inequality of terminal in the sub-district is in subframe lengths T, specifically can realize by plot planning, when carrying out plot planning, divide by the sub-district, calculate the center time delay of division of cells, center time delay difference by making neighbor cell is at subframe lengths T, realizes in the sub-district that the one way propagation delay inequality of terminal is in subframe lengths T in the sub-district.

Embodiment 2

Insert tdma system in time division multiplexing, the transmission of the last data of UpPTS need guarantee the regular hour precision.Preferably, when terminal is communicated by letter based on the uplink/downlink frames of above-mentioned FDD mode with the base station in the present embodiment,, need to guarantee the transmitting time precision of uplink synchronous code SYNC_UL in order to realize uplink synchronous exactly.

Particularly, in the present embodiment, the base station is with center time delay terminal in descending sub frame is broadcast to the sub-district of sub-district, and the center time delay of described sub-district is determined according to the distance between the center of base station and sub-district, place, base station; Terminal when inserting at random with the center time delay of base station broadcast as RTT, and according to definite time that sends uplink synchronous code SYNC_UL of described RTT, and the selection ascending pilot channel UpPCH corresponding with uplink synchronous code SYNC_UL, send uplink synchronous code SYNC_UL at sub-frame of uplink.

Therefore, by fixing center time delay of network side broadcasting (corresponding center time delay in sub-district, the center time delay difference of different districts), terminal is determined the starting point of subframe up and down according to fixing center time delay, because terminal sends SYNC_UL at concrete which time slot position of sub-frame of uplink, configures in advance, therefore, terminal comprised according to the time that RTT determines to send uplink synchronous code SYNC_UL in the present embodiment:

Determine the leading current time starting point x transmission uplink synchronous code SYNC_UL of a descending sub frame afterwards, wherein:

X=(RTT-(time that the relative sub-frame of uplink starting point of the SYNC_UL of setting lags behind)) mod (subframe lengths T).

As seen, the position of the transmission SYNC_UL that calculates in a manner described is the time location that the relative sub-frame of uplink starting point of the SYNC_UL that sets in the sub-frame of uplink lags behind.

Because it is to determine according to the center time delay of base station broadcast that terminal sends the time of SYNC_UL, requires the propagation delay of terminal in the sub-district to control within the specific limits.Preferably, the propagation delay of terminal satisfies the restriction that embodiment 1 is given in the sub-district: the one way propagation delay inequality of terminal is in subframe lengths T in the sub-district; It is surplus that the division of sub-district makes the one way propagation time delay of all terminals in the sub-district get subframe lengths T, and (0=＜remainder＜T/2), (terminal between T/2=＜remainder＜T) is in the another one sub-district to T at T/2 for remainder a sub-district for the terminal of remainder in T/2.

Further, in order to make network side correctly receive the SYNC_UL that terminal sends, the one way propagation time delay of cell terminal also satisfies following condition in the present embodiment: the division of sub-district is not more than the one way propagation delay inequality of all terminals in the sub-district and sends 1/2 of SYNC_UL permission jitter range.

Sending SYNC_UL permission jitter range is by the number of chips of the Time Slot Occupancy that allows transmission (the prior setting) SYNC_UL in the sub-frame of uplink, deducts the shared number of chips of SYNC_UL transmission and determines.

Generally, allowing the time slot of transmission SYNC_UL is UpPTS, in order to enlarge the coverage of sub-district, can expand the time range that SYNC_UL allows to send, and promptly allows SYNC_UL to insert at some adjacent uplink service time slots.As the time slot that allows to send SYNC_UL is 1 uplink service time slot after the UpPTS+UpPTS, or be UpPTS+UpPTS 2 uplink service time slots afterwards.

Present embodiment allows 1/2 of jitter range by the center time delay difference that makes neighbor cell at SYNC_UL, realizes that the one way propagation delay inequality of all terminals in the sub-district is not more than 1/2 of transmission SYNC_UL permission jitter range.

With the satellite system is example, for satellite system following data is arranged:

China's latitude scope is: north latitude 4-north latitude 53;

China's longitude scope is: east longitude 73-east longitude 135;

Can suppose that in analysis the satellite position is: north latitude 0, east longitude 104.

As shown in table 1, the SYNC_UL of correspondence allows the one way propagation delay inequality of terminal in jitter range and the sub-district when being different situations for the time slot that allows transmission SYNC_UL.

Table 1SYNC_UL allows the one way propagation delay inequality of terminal in jitter range and the sub-district

In the table 1, special time slot refers to that SYNC_UL can move in 352 chip of special time slot UpPTS, since terminal is to be with the descending sub frame benchmark in advance 2 one way propagation time delays send sub-frame of uplink, so will allow the delay inequality that terminal allows in the sub-district be 1/2 of SYNC_UL permission jitter range.

Move in the scope of the uplink service time slot 1 of time slot 1 finger SYNC_UL permission after special time slot UpPTS+UpPTS.

Move in the scope of the uplink service time slot 2 after the time slot 2 uplink service time slot 1+UpPTS+UpPTS of finger SYNC_UL permission after special time slot+UpPTS+UpPTS.

When providing delay inequality with cell terminal below and being controlled within the different delay difference, pairing sub-district dividing condition.

As shown in table 2, the relation of cell diameter and latitude when being 87.5 microseconds for delay inequality, time delay value in the table is the center time delay of the sub-district of division, its corresponding dimension angle and spacing has been determined cell range, wherein the lookup method of longitude is: | longitude-104|, so Chinese longitude scope is 0-31 in following table.

The relation of cell diameter and latitude when table 2 delay inequality is 87.5 microseconds

Time delay value (microsecond)	Dimension angle (degree)	Spacing (kilometer)
			119543.56	1.20742E-06	0
119631.06	4.792059372	533.4383509
			119718.56	6.78021491	221.3158471
119806.06	8.307982792	170.0667962
			119893.56	9.597799732	143.578771
119981.06	10.73578106	126.6768605
			120068.56	11.76607074	114.6889304
120156.06	12.71488002	105.6187632
			120243.56	13.59927913	98.44880562
120331.06	14.43111971	92.59813973

120418.56	15.21902703	87.70761231
			120506.06	15.96950956	83.5415915
120593.56	16.68762156	79.93819444
			120681.06	17.37738065	76.78202945
120768.56	18.04204293	73.98832391
			120856.06	18.68429076	71.49321115
120943.56	19.30636494	69.2475367
			121031.06	19.91016011	67.21276951
121118.56	20.49729525	65.35822158
			121206.06	21.06916667	63.65910825
121293.56	21.62698866	62.09516437
			121381.06	22.17182498	60.64963736
121468.56	22.70461379	59.30854155
			121556.06	23.22618739	58.06009723
121643.56	23.73728826	56.89430279
			121731.06	24.23858204	55.80260399
121818.56	24.73066817	54.77763551
			121906.06	25.21408881	53.81301671
121993.56	25.68933615	52.90318869
			122081.06	26.15685866	52.04328312
122168.56	26.61706634	51.22901582
			122256.06	27.07033514	50.45659968
122343.56	27.51701082	49.72267293

122431.06

27.95741224

49.0242397

As shown in table 3, the relation of cell diameter and latitude when being 425 microseconds for delay inequality, the time delay value in the table is the center time delay of the sub-district of division, its corresponding dimension angle and spacing has been determined cell range.

The relation of cell diameter and latitude when table 3 delay inequality is 425 microseconds

Time delay value (microsecond)	Dimension angle (degree)	Spacing (kilometer)
			119543.56	1.20742E-06	0
119968.56	10.58058068	1177.800159
			120393.56	14.99798241	491.7326562
120818.56	18.41163374	379.9980046
			121243.56	21.30988841	322.6255057
121668.56	23.88148841	286.2632332
			122093.56	26.22304134	260.6550451
122518.56	28.39183418	241.4238796
			122943.56	30.42513284	226.3410513
123368.56	32.34878596	214.1356213
			123793.56	34.18159136	204.0227087
124218.56	35.9377262	195.4879598
			124643.56	37.62819697	188.1784211
125068.56	39.26175281	181.8428123
			125493.56	40.84548665	176.2967684
125918.56	42.38524536	171.4015818
			126343.56	43.88591822	167.0506547
126768.56	45.35164504	163.1605614

127193.56	46.78596982	159.6649742
			127618.56	48.19195624	156.5104283
128043.56	49.57227612	153.6533027
			128468.56	50.92927814	151.0576239
128893.56	52.26504191	148.693442
			129318.56	53.58142113	146.5356086

In this case, the number of cells that covering China needs is about 920, has certain realizability.

As shown in table 4, the relation of cell diameter and latitude when being 762 microseconds for delay inequality, the time delay value in the table is the center time delay of the sub-district of division, its corresponding dimension angle and spacing has been determined cell range.

The relation of cell diameter and latitude when table 4 delay inequality is 762 microseconds

Time delay value (microsecond)	Dimension angle (degree)	Spacing (kilometer)
			119543.56	1.20742E-06	0
120306.06	14.19826423	1580.510451
			121068.56	20.16374345	664.0602616
121831.06	24.80024681	516.1224313
			122593.56	28.75964427	440.7489175
123356.06	32.29358377	393.3881429
			124118.56	35.53079096	360.3567412
124881.06	38.54759532	335.8221224
			125643.56	41.39368256	316.818376
126406.06	44.10356699	301.6566638
			127168.56	46.70241015	289.2958648
127931.06	49.20925776	279.0551807
			128693.56	51.63897025	270.4687162

129456.06

54.00343878

263.2059446

In this case, cover the Chinese number of cells that needs and be about 260.

Embodiment 3

Provide in the present embodiment when base station and terminal communicate based on above-mentioned FDD mode frame structure under the long time delay, realized synchronously and random access procedure.As shown in Figure 7, specifically comprise the steps:

Step S701, when terminal inserts at random with the center time delay of base station broadcast as RTT, and, select the ascending pilot channel UpPCH corresponding, at sub-frame of uplink transmission uplink synchronous code SYNC_UL with uplink synchronous code SYNC_UL according to the time that described RTT determines to send uplink synchronous code SYNC_UL;

Particularly, terminal is determined the leading current time starting point x transmission uplink synchronous code SYNC_UL of a descending sub frame afterwards, wherein:

Terminal can be selected one at random from the corresponding available UpPCH subchannel of given ASC, uplink synchronous code SYNC_UL is corresponding with UpPCH, and must to satisfy each available selected probability of UpPCH subchannel identical for used random function during selection.The count value and the signature transmitting power of signature retransmission counter also can be set certainly.

Step S702 when terminal sends SYNC_UL and waits for RTT, detects the timed message of whether receiving on the FPACH in N descending sub frame subsequently, if, execution in step S704, if not, execution in step S705.

After terminal sent SYNC_UL and waits for RTT in the present embodiment, beginning received data on the FPACH at descending sub frame.Be different from the existing upward data of FPACH that directly begin to receive.Concrete Time Calculation is, UE will find the descending sub frame number of the fastest feedback of network side FPACH according to the time delay relation, and receives FPACH in this descending sub frame and subsequently (N-1) individual subframe thereof and go up data.Because this moment, terminal was not also known RTT accurately, so replace RTT with the center time delay of network side broadcasting.

For the base station, in N descending sub frame of the setting quantity of base station after receiving SYNC_UL, with the corresponding rapid physical Acquisition Indicator Channel of the UpPCH FPACH that receives SYNC_UL, send and carry the timed message of the time deviation that is used for modified R TT.According to existing standard, SYNC_UL is corresponding one by one with UpPCH, and UpPCH is corresponding one by one with FPACH, and FPACH is corresponding one by one with PRACH.According to existing standard, above-mentioned setting quantity N is 4.

Particularly, the base station will send timed message from the descending sub frame that satisfies following relationship, and terminal will read the timed message on the FPACH from the descending sub frame that satisfies following relationship:

SFN′mod?L _i＝n _RACHi，n _RACHi＝0，...，N _RACHi-1

Base station in the present embodiment is returned timed message at FPACH to terminal, carries the time deviation that is used for modified R TT, so that terminal is carried out chip-level is synchronous.The method of determining time deviation in the prior art behind the reception SYNC_UL can be adopted, the time deviation of the reference time in first footpath of receiving as connecting from the UpPCH measurement according to the method that the SYNC_UL that receives determines the time deviation of RTT in the base station.Preferably, also carry coding and the concrete number of sub frames WT that waits in base station of the SYNC_UL that is responded on the FPACH.Terminal can determine whether it is the response of oneself according to the coding of SYNC_UL like this, determines the transmitting time of the SYNC_UL that the base station responds according to number of sub frames WT, thereby determines whether the Signature Confirmation into oneself.

SYNC_UL and WT message can be continued to use the definition mode of the corresponding message of existing TD-SCDMA system among the FPACH.

Step S703, if do not detect effective response within the scheduled time, the count value of signature retransmission counter subtracts 1.Whether the count value of judging the signature retransmission counter still greater than 0, if, return execution in step S701, otherwise execution in step S704.

Step S704 reports once access failure at random to MAC (Media Access Control, medium access control) layer.

Step S705 when terminal is determined to receive timed message, according to the time deviation modified R TT in the timed message, and adjusts the starting point of sub-frame of uplink and descending sub frame according to revised RTT.

What this step realized is that chip-level is synchronous, specifically assists with the timed message among the FPACH and finishes.With time deviation modified R TT in the timed message, redefine the starting point of sub-frame of uplink and descending sub frame, the transmitting time of RACH message, by the sending time slots of network side indication, and RTT and the correction determined according to timed message determine jointly.

Step S706 adjusts back terminal 2 or 3 sub-frame of uplink in interval after receiving timed message, sends Random Access Channel RACH message on the corresponding Physical Random Access Channel PRACH of FPACH.

Particularly, if the length of the RACH message that will send is greater than 1, and receive that the subframe numbers of the descending sub frame of timed message is an odd number, 3 sub-frame of uplink send the RACH message at interval, otherwise 2 sub-frame of uplink send the RACH message at interval.

The sending time slots of SYNC_UL is generally at special time slot UpPTS, situation for time slot 1 that is arranged in the above embodiment of the present invention and time slot 2, the timed message that also needs spread F PACH, to support it to carry the coding of SYNC_UL, as among the spread F PACH regularly indication bit is 14 bits, the first adjustment precision that perhaps reduces behind the SYNC_UL is 1/4chip.

The terminal that the present invention also provides the carrying out under a kind of long time delay to insert at random, comprise: the time-delay determining unit, be used for according to the two-way time delay RTT between terminal and base station, determine to send the time of uplink synchronous code SYNC_UL, described RTT obtains by system broadcasts, or described RTT is pre-defined value; Access unit is used to select the ascending pilot channel UpPCH corresponding with SYNC_UL at random, sends SYNC_UL on the UpPCH that selects, and carries out random access procedure.

Preferably, this terminal also comprises: detecting unit, be used for when sending SYNC_UL and waiting for RTT, and in N descending sub frame of setting quantity subsequently, detect the timed message of whether receiving on the rapid physical Acquisition Indicator Channel FPACH; Amending unit, when being used to determine to receive timed message, according to the time deviation modified R TT in the timed message, and according to revised RTT adjustment sub-frame of uplink and descending sub frame starting point; Response unit is used to adjust back terminal 2 or 3 sub-frame of uplink in interval after receiving timed message, sends Random Access Channel RACH message on the corresponding Physical Random Access Channel PRACH of FPACH.

Those skilled in the art should understand that embodiments of the invention can be provided as method, system or computer program.Therefore, the present invention can adopt complete hardware embodiment, complete software implementation example or in conjunction with the form of the embodiment of software and hardware aspect.And the present invention can adopt the form that goes up the computer program of implementing in one or more computer-usable storage medium (including but not limited to magnetic disc store, CD-ROM, optical memory etc.) that wherein include computer usable program code.

The present invention is that reference is described according to the flow chart and/or the block diagram of method, equipment (system) and the computer program of the embodiment of the invention.Should understand can be by the flow process in each flow process in computer program instructions realization flow figure and/or the block diagram and/or square frame and flow chart and/or the block diagram and/or the combination of square frame.Can provide these computer program instructions to the processor of all-purpose computer, special-purpose computer, Embedded Processor or other programmable data processing device to produce a machine, make the instruction of carrying out by the processor of computer or other programmable data processing device produce to be used for the device of the function that is implemented in flow process of flow chart or a plurality of flow process and/or square frame of block diagram or a plurality of square frame appointments.

These computer program instructions also can be stored in energy vectoring computer or the computer-readable memory of other programmable data processing device with ad hoc fashion work, make the instruction that is stored in this computer-readable memory produce the manufacture that comprises command device, this command device is implemented in the function of appointment in flow process of flow chart or a plurality of flow process and/or square frame of block diagram or a plurality of square frame.

These computer program instructions also can be loaded on computer or other programmable data processing device, make on computer or other programmable devices and to carry out the sequence of operations step producing computer implemented processing, thereby the instruction of carrying out on computer or other programmable devices is provided for being implemented in the step of the function of appointment in flow process of flow chart or a plurality of flow process and/or square frame of block diagram or a plurality of square frame.

Although described the preferred embodiments of the present invention, in a single day those skilled in the art get the basic creative notion of cicada, then can make other change and modification to these embodiment.So claims are intended to all changes and the modification that are interpreted as comprising preferred embodiment and fall into the scope of the invention.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims

1. the accidental access method under the long time delay is characterized in that, comprising:

2. the method for claim 1, it is characterized in that, FDD is adopted in terminal and base station in this method, carry out transmitting uplink data based on sub-frame of uplink, simultaneously carry out downlink data transmission based on descending sub frame, described sub-frame of uplink comprises the uplink pilot time slot UpPTS that is used for uplink synchronous and is used to transmit the uplink service time slot of uplink user data, and described descending sub frame comprises the down link pilot timeslot DwPTS that is used for down-going synchronous and with the downlink business time slot that transmits down user data.

3. method as claimed in claim 2 is characterized in that the length of described sub-frame of uplink and descending sub frame is 5ms, and sub-frame of uplink comprises 1 UpPTS and 7 uplink service time slots, and descending sub frame comprises 1 DwPTS and 7 downlink business time slots.

4. method as claimed in claim 2 is characterized in that, terminal based on the sub-frame of uplink starting point shift to an earlier date RTT than descending sub frame starting point, the base station based on sub-frame of uplink and the definitely alignment in time of the starting point of descending sub frame; And sub-frame of uplink is identical with the subframe lengths T of descending sub frame, terminal based on the sub-frame of uplink starting point than the base station based on the sub-frame of uplink starting point shift to an earlier date RTT/2.

5. as the arbitrary described method of claim 1～4, it is characterized in that terminal specifically comprised according to the time that described RTT determines to send uplink synchronous code SYNC_UL:

T is the subframe lengths of sub-frame of uplink and descending sub frame.

6. as the arbitrary described method of claim 1～4, it is characterized in that terminal sends after the SYNC_UL, also comprises:

7. method as claimed in claim 6 is characterized in that, described N is 4, if the length of the RACH message that will send is greater than 1, and the subframe numbers of receiving the descending sub frame of timed message is an odd number, and 3 sub-frame of uplink send RACH message at interval, otherwise 2 sub-frame of uplink send RACH message at interval.

8. as the arbitrary described method of claim 1～4, it is characterized in that terminal obtains described RTT by system broadcast message, specifically comprises:

9. as the arbitrary described method of claim 2～4, it is characterized in that, in this method, terminal determines that on absolute time a pair of sub-frame of uplink and the descending sub frame that satisfy following condition are considered as same subframe: the time range＜subframe lengths T of the leading descending sub frame of 0ms=＜sub-frame of uplink.

10. method as claimed in claim 9 is characterized in that, terminal determines that the method for next sub-frame of uplink/descending sub frame is in this method:

11., it is characterized in that the division of sub-district makes the one way propagation delay inequality of all terminals in the same sub-district in subframe lengths T as the arbitrary described method of claim 1～4.

12. method as claimed in claim 11 is characterized in that, it is surplus that the division of sub-district makes the one way propagation time delay of all terminals in the sub-district get T, and the terminal of remainder in T/2 be a sub-district, remainder at T/2 to the terminal between T in the another one sub-district.

13. method as claimed in claim 11 is characterized in that, the division of sub-district is not more than the one way propagation delay inequality of all terminals in the sub-district and sends 1/2 of SYNC_UL permission jitter range.

14. method as claimed in claim 13 is characterized in that, described transmission SYNC_UL allows the number of chips of jitter range by the Time Slot Occupancy that allows transmission SYNC_UL in the sub-frame of uplink, deducts the shared number of chips of SYNC_UL transmission and determines.

15. method as claimed in claim 14 is characterized in that, the time slot that described permission sends SYNC_UL is UpPTS, or is 1 uplink service time slot after the UpPTS+UpPTS, or is 2 uplink service time slots after the UpPTS+UpPTS.

16. method as claimed in claim 13, it is characterized in that, in the microzonation timesharing, allow 1/2 of jitter range by the center time delay difference that makes neighbor cell at SYNC_UL, realize that the one way propagation delay inequality of all terminals in the sub-district is not more than 1/2 of transmission SYNC_UL permission jitter range.

17. the terminal that the carrying out under the long time delay inserted at random is characterized in that, comprising:

18. terminal as claimed in claim 17, it is characterized in that, each unit in the described terminal adopts FDD, carry out transmitting uplink data based on sub-frame of uplink, simultaneously carry out downlink data transmission based on descending sub frame, described sub-frame of uplink comprises the uplink pilot time slot UpPTS that is used for uplink synchronous and is used to transmit the uplink service time slot of uplink user data, and described descending sub frame comprises the down link pilot timeslot DwPTS that is used for down-going synchronous and with the downlink business time slot that transmits down user data.

19. terminal as claimed in claim 18, it is characterized in that, each unit in the described terminal based on the sub-frame of uplink starting point shift to an earlier date RTT than descending sub frame starting point, each unit in the described terminal based on the sub-frame of uplink starting point than the base station based on the sub-frame of uplink starting point shift to an earlier date RTT/2, the base station based on sub-frame of uplink and the definitely alignment in time of the starting point of descending sub frame, and sub-frame of uplink is identical with the subframe lengths T of descending sub frame.

20. as the arbitrary described terminal of claim 17～19, it is characterized in that, described time-delay determining unit specifically is used for determining the leading current time starting point x transmission SYNC_UL of a descending sub frame afterwards, wherein: x=(RTT-(time that the relative sub-frame of uplink starting point of the SYNC_UL of setting lags behind)) mod (T), T is the subframe lengths of sub-frame of uplink and descending sub frame.

21. as the arbitrary described terminal of claim 17～19, it is characterized in that, also comprise:

22. as the arbitrary described terminal of claim 17～19, it is characterized in that, described time-delay determining unit specifically is used for obtaining the center time delay according to the receiving system broadcast, and determine RTT according to described center time delay, described center time delay is determined according to the distance between the center of base station and sub-district, place, base station.

23. as claim 18 or 19 described terminals, it is characterized in that, also comprise:

Same subframe determining unit is used to determine in absolute time, and a pair of sub-frame of uplink and the descending sub frame that satisfy following condition are considered as same subframe: the time range＜subframe lengths T of the leading descending sub frame of 0ms=＜sub-frame of uplink.

24. terminal as claimed in claim 20 is characterized in that, also comprises:

Next subframe determining unit is used for determining current sub-frame of uplink and the descending sub frame that is considered as same subframe, and determines that the sub-frame of uplink/descending sub frame after the same subframe is next sub-frame of uplink/descending sub frame.

25., it is characterized in that the one way propagation delay inequality of all terminals is in subframe lengths T in the sub-district, described terminal place as the arbitrary described terminal of claim 17～19.

26. terminal as claimed in claim 25 is characterized in that, the one way propagation time delay of all terminals is got surplusly in the sub-district, described terminal place to T, and the terminal of remainder in T/2 be a sub-district, remainder at T/2 to the terminal between T in the another one sub-district.

27. terminal as claimed in claim 25 is characterized in that, the one way propagation delay inequality of all terminals is not more than and sends 1/2 of SYNC_UL permission jitter range in the sub-district, described terminal place.