CN102076058B

CN102076058B - Random access method under large time delay and terminal

Info

Publication number: CN102076058B
Application number: CN 201110044646
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: 2013-06-12
Anticipated expiration: 2031-02-23
Also published as: CN102076058A

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 the DwPTS(Downlink Pilot Time Slot for down-going synchronous; down link pilot timeslot), be used for preventing the protection time slot Main GP that disturbs between uplink and downlink signals, the UpPTS(Downlink Pilot Time Slot that is used for uplink synchronous, down link pilot timeslot) and be used for the conventional time slot TS0 ~ TS6 of transmitting user data.

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

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) at random in subchannel select one, during selection, must to satisfy each available selected probability of UpPCH subchannel identical for random function used;

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

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

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

SFN'modL _i=n _RACHi，n _RACHi=0,...,N _RACHi-1

Wherein SFN' is subframe numbers, L _iBe n _RACHiIndividual RACH(Random Access Channel, Random Access Channel) length of 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, the effective response of network side namely whether detected, if not, and execution in step S206, otherwise execution in step S207.

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

Step S207 is to MAC(Media Access Control, media access control) random access failure of layer report.

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

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

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

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

SFN'modL _i=n _RACHi，n _RACHi=0,...,N _RACHi-1

Wherein SFN' is 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 random access request 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 at the UpPTS time slot, and send accidental access response on the relevant FPACH of UpPCH.

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

Because UE is random access, conflict most possibly occurs in the UpPCH time slot that sends SYNC_UL, and RACH RU(RACH Resource Unit) probability that clashes reduces greatly, and can guarantee that RACH RU can be in same UL time slot and conventional business co-treatment.

When the conflict possibility is larger, 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 namely UE transmission of the subframe 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; the value at protection interval is 0.075ms+N*5ms, needs protection interval between DwPTS and UpPTS to be greater than and equals the two-way propagation time delay, under the condition of fixed statellite; this value is greater than 200ms.Will be arranged like this by vacant the above time of 200ms in each subframe, may bring a large amount of wastings of resources or can't work, system effectiveness is lower.

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

1) present TD-SCDMA system judges time delay according to path loss, but the calculating of path loss can be subject to the impact 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, for geosynchronous satellite, propagation delay evaluated error more than 31ms will be arranged.

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, if also adopt path loss to judge time delay, the propagation delay evaluated error is excessive, may cause actual SYNC_UL arrive base station (satellite) the time be engraved in 5ms frame any position, like this uplink service time slot is brought interference, base station (satellite) also may lose SYNC_UL.

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

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, to receive FPACH in 4 subframes subsequently by existing standard, UE can't receive accidental access response on oneself FPACH so, but also the upper accidental access response of the FPACH that might by mistake receive other UE, thereby cause the collision of PRACH, or incorrect other uplink service time slots are produced of the transmitting time of PRACH disturbed.

Above-mentioned two situations all can cause system to work.

Summary of the invention

The invention provides accidental access method and terminal under a kind of long time delay, in order to solve in 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, determine the leading current time starting point x transmission SYNC_UL of a descending sub frame afterwards, described terminal obtains described RTT by system broadcasts, or described RTT is pre-defined value, wherein: the time that the relative sub-frame of uplink starting point of the SYNC_UL that x=(RTT-(sets lags behind)) mod(T), T is the subframe lengths of sub-frame of uplink and descending sub frame;

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, in the method, FDD is adopted in terminal and base station, 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 that for the uplink pilot time slot UpPTS of uplink synchronous with for the uplink service time slot that transmits uplink user data, described descending sub frame comprises for the down link pilot timeslot DwPTS of down-going synchronous with for 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 also comprises after sending SYNC_UL:

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

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

Terminal interval 2 or 3 sub-frame of uplink after receiving timed message after adjusting send Random Access Channel RACH message on the corresponding Physical Random Access Channel PRACH of FPACH.

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

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 residential quarter, place, base station.

Preferably, in the method, terminal determines on 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 of the leading descending sub frame of 0ms=＜sub-frame of uplink＜subframe lengths T.

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

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 same subframe is next sub-frame of uplink/descending sub frame.

Preferably, the division of residential quarter makes the one way propagation delay inequality of all terminals in same residential quarter in subframe lengths T.

Preferably, the division of residential quarter makes the one way propagation time delay of all terminals in the residential quarter to the T remainder, and the terminal of remainder in T/2 be a residential quarter, remainder at T/2 to the terminal between T in the another one residential quarter.

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

Preferably, described transmission SYNC_UL allows jitter range by the number of chips of the Time Slot Occupancy that allows transmission SYNC_UL in 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 UpPTS+UpPTS, or is 2 uplink service time slots after UpPTS+UpPTS.

Preferably, 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 residential quarter is not more than 1/2 of transmission SYNC_UL permission jitter range.

The present invention also provides the terminal of the random access of carrying out under a kind of long time delay, comprising:

The time-delay determining unit, be used for according to the two-way time delay RTT between terminal and base station, determine the leading current time starting point x transmission SYNC_UL of a descending sub frame afterwards, described RTT obtains by system broadcasts, or described RTT is pre-defined value, wherein: the time that the relative sub-frame of uplink starting point of the SYNC_UL that x=(RTT-(sets lags behind)) mod(T), T is the subframe lengths of sub-frame of uplink and descending sub frame;

Random access unit is used for selecting the ascending pilot channel UpPCH corresponding with SYNC_UL, sends SYNC_UL on the UpPCH that selects, and carries out random access procedure.

Preferably, each unit in 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 that for the uplink pilot time slot UpPTS of uplink synchronous with for the uplink service time slot that transmits uplink user data, described descending sub frame comprises for the down link pilot timeslot DwPTS of down-going synchronous with for the downlink business time slot that transmits down user data.

Preferably, each unit in 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 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, 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 rapid physical Acquisition Indicator Channel FPACH in N descending sub frame of setting quantity subsequently;

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

Response unit, terminal interval 2 or 3 sub-frame of uplink after receiving timed message after being used for adjusting send 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 residential quarter, place, base station.

Preferably, this terminal also comprises: same subframe determining unit, be used for determining 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 of the leading descending sub frame of 0ms=＜sub-frame of uplink＜subframe lengths T.

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 same subframe is next sub-frame of uplink/descending sub frame.

Preferably, in residential quarter, terminal place the one way propagation delay inequality of all terminals in subframe lengths T.

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

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

Utilize method and the terminal of random access under long time delay provided by the invention, have following beneficial effect: avoided realizing the accurate synchronization of network side and terminal to the waste of system resource and because the up-downgoing data of the inaccurate formation of time delay estimation are disturbed.

Description of drawings

Fig. 1 is for having the subframe structure schematic diagram of TD-SCDMA system now;

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

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

Fig. 4 is the descending sub frame structural representation that the embodiment of the present invention adopts;

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

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

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

Embodiment

Below in conjunction with drawings and Examples, the accidental access method under 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 namely UE transmission of the subframe SYNC_UL of SYNC_UL.(the one way propagation time delay of terminal to base station surpasses TDMA(Time Division Multiple Access and at long time delay; time division multiplexing) system at protection interval) in situation; the TD-SCDMA system can cause SYNC_UL arrive the base station the time be engraved in 5ms frame any position, upstream data formed to disturb 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 residential quarter, place, base station.

Preferably, in the method, FDD (Frequency Division Duplexing is adopted in terminal and base station, 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 for the uplink pilot time slot UpPTS of uplink synchronous and is used for the uplink service time slot of transmission uplink user data, and described descending sub frame comprises for the down link pilot timeslot DwPTS of down-going synchronous 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.

When in the TDD mode of TD-SCDM, propagation delay is larger, problem that system resource waste is serious, so need to introduce the frame structure of FDD mode.In the embodiment of the present invention under the long time delay environment; the frame structure of FDD mode is introduced in terminal and data communication; in the descending sub frame structure, all time slots all are used for sending downlink data; in the sub-frame of uplink structure, all time slots all are used for sending upstream data; 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 greatly protecting time slot to arrange 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 while terminal and the ascending-descending subframes of network side, the transceiving data time consistency that end side and network side are understood has realized that the data between terminal and base station are synchronous.

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 from the angle of compatibility, in the present embodiment, the FDD mode with respect to the subframe structure of TDD, remains unchanged for the special time slot DwPTS of descending sub frame structure; 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 the 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 namely terminal transmission of the subframe SYNC_UL of SYNC_UL.And in the communication system of long time delay, according to the data communications method under 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 concept that needs to use next frame or two frames in the processes such as random access, equally because terminal is no longer alignd on ascending-descending subframes with the base station, the present embodiment is used some concepts to the terminal random access procedure and is redefined, according to the needs of physical layer relevant control, to base station and terminal based on the ascending-descending subframes correlation timing be defined as follows:

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, due to from the base station between propagation delay different and different.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 is defined as follows:

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 rear sub-frame of uplink of sub-frame of uplink in same subframe, and on down direction, next descending sub frame is rear one descending subframe of descending sub frame in same subframe.

In the embodiment of the present invention, terminal is determined the method for next sub-frame of uplink/descending sub frame, and under being equally applicable to determine, two or three wait and set quantity sub-frame of uplink/descending sub frame.

When the terminal of diverse location and base station communication based on the starting point of ascending-descending subframes, due to from the base station between propagation delay different and different.Preferably, in the present embodiment, the base station is with center time delay terminal in descending sub frame is broadcast to the residential quarter of residential quarter, and the center time delay of described residential quarter is determined according to the distance between the center of base station and residential quarter, place, base station; Terminal when random access with the center time delay of base station broadcast as RTT.Preferably, the base station is in first time slot broadcasting center of subframe time delay, 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, known as the satellite of base station longitude and latitude of living in, therefore the coverage of each residential quarter is known when plot planning, by the distance between Calculation of Satellite and each center of housing estate position, just can accurately calculate the electromagnetic wave propagation time delay.

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

RTT and the actual RTT error thought when accessing for further minimizing terminal initial in the present embodiment, the division of residential quarter makes the one way propagation time delay of all terminals in the residential quarter to subframe lengths T remainder, the terminal of remainder in T/2 a residential quarter (0=＜remainder＜T/2), remainder at T/2 to the terminal between T(T/2=＜remainder＜T) in the another one residential quarter.

The embodiment of the present invention realizes that the one way propagation delay inequality of terminal in the residential quarter is in subframe lengths T, specifically can realize by plot planning, when carrying out plot planning, divide by the residential quarter, 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 residential quarter that in the residential quarter, the one way propagation delay inequality of terminal is in subframe lengths T.

Embodiment 2

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

Particularly, in the present embodiment, the base station is with center time delay terminal in descending sub frame is broadcast to the residential quarter of residential quarter, and the center time delay of described residential quarter is determined according to the distance between the center of base station and residential quarter, place, base station; Terminal when random access with the center time delay of base station broadcast as RTT, and the time that sends uplink synchronous code SYNC_UL definite according to 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, broadcast a fixing center time delay (corresponding center time delay in residential quarter by network side, the center time delay of different districts is different), terminal is determined the starting point of up and down subframe according to fixing center time delay, send SYNC_UL due to terminal at concrete which time slot position of sub-frame of uplink, set in advance, therefore, in the present embodiment, terminal according to the time that RTT determines to send uplink synchronous code SYNC_UL, comprising:

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

The time that the relative sub-frame of uplink starting point of the SYNC_UL that x=(RTT-(sets 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 sub-frame of uplink lags behind.

The time that sends SYNC_UL due to terminal is to determine according to the center time delay of base station broadcast, requires the propagation delay of terminal in the residential quarter to control within the specific limits.Preferably, in the residential quarter propagation delay of terminal satisfy embodiment 1 to restriction: in the residential quarter, the one way propagation delay inequality of terminal is in subframe lengths T; The division of residential quarter makes the one way propagation time delay of all terminals in the residential quarter to subframe lengths T remainder, the terminal of remainder in T/2 a residential quarter (0=＜remainder＜T/2), remainder at T/2 to the terminal between T(T/2=＜remainder＜T) in the another one residential quarter.

Further, in order to make network side correctly receive the SYNC_UL that terminal sends, the one way propagation time delay of the present embodiment small area terminal also satisfies following condition: the division of residential quarter is not more than the one way propagation delay inequality of all terminals in the residential quarter 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 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 residential quarter, can expand the time range that SYNC_UL allows to send, and namely allows SYNC_UL in some adjacent uplink service time slots accesses.As the time slot that allows to send SYNC_UL is 1 uplink service time slot after UpPTS+UpPTS, or be UpPTS+UpPTS 2 uplink service time slots afterwards.

The 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 residential quarter is not more than 1/2 of transmission SYNC_UL permission jitter range.

Take satellite system as example, for satellite system, following data are 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, when being different situations for the time slot that allows transmission SYNC_UL, corresponding SYNC_UL allows the one way propagation delay inequality of terminal in jitter range and residential quarter.

Table 1SYNC_UL allows the one way propagation delay inequality of terminal in jitter range and residential quarter

In table 1, special time slot refers to that SYNC_UL can move in 352 chip of special time slot UpPTS, because terminal is will shift to an earlier date take descending sub frame as benchmark 2 one way propagation time delays to send sub-frame of uplink, so will allow the delay inequality that terminal allows in the residential quarter 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.

The below provide delay inequality with cell terminal be controlled at different delay poor within the time, corresponding residential quarter dividing condition.

As shown in table 2, the relation of cell diameter and latitude when being 87.5 microsecond for delay inequality, time delay value in table is the center time delay of the residential quarter 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 microsecond

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 microsecond for delay inequality, the time delay value in table is the center time delay of the residential quarter 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 microsecond

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 microsecond for delay inequality, the time delay value in table is the center time delay of the residential quarter 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 microsecond

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

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

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 UpPCH subchannel corresponding to given ASC, and uplink synchronous code SYNC_UL is corresponding with UpPCH, and during selection, must to satisfy each available selected probability of UpPCH subchannel identical for random function used.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 FPACH in N descending sub frame subsequently, if, execution in step S704, if not, execution in step S705.

After in the present embodiment, terminal sent SYNC_UL and waits for RTT, beginning received data on FPACH at descending sub frame.Be different from the existing upper data of FPACH that directly begin to receive.Concrete Time Calculation is, UE will find network side to feed back the soonest the descending sub frame number of FPACH according to the time delay relation, and receives the upper data of FPACH at this descending sub frame and subsequently (N-1) individual subframe thereof.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 the timed message that carries for the time deviation of 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 FPACH from the descending sub frame that satisfies following relationship:

SFN'modL _i=n _RACHi，n _RACHi=0,...,N _RACHi-1

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

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

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

Step S704 is to MAC(Media Access Control, media access control) random access failure of layer report.

Step S705 when terminal is determined to receive timed message, according to the time deviation modified R TT in 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 in FPACH and completes.With time deviation modified R TT in 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, reaches RTT and jointly determines according to the definite correction of timed message.

Step S706, terminal interval 2 or 3 sub-frame of uplink after receiving timed message after adjusting send 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 greater than 1, and receives that the subframe numbers of the descending sub frame of timed message is odd number, 3, interval sub-frame of uplink sends RACH message, otherwise 2, interval sub-frame of uplink sends RACH message.

The sending time slots of SYNC_UL is generally at special time slot UpPTS, situation for the 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 in spread F PACH regularly indication bit be 14 bits, the first adjustment precision that perhaps reduces after SYNC_UL is 1/4chip.

The present invention also provides the terminal of the random access of carrying out under a kind of long time delay, 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; Random access unit is used for selecting the ascending pilot channel UpPCH corresponding with SYNC_UL, sends SYNC_UL on the UpPCH that selects, and carries out random access procedure.

Preferably, each unit in 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 for the uplink pilot time slot UpPTS of uplink synchronous and is used for the uplink service time slot of transmission uplink user data, and described descending sub frame comprises for the down link pilot timeslot DwPTS of down-going synchronous with the downlink business time slot that transmits down user data.

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: the time that the relative sub-frame of uplink starting point of the SYNC_UL that x=(RTT-(sets 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, be used for when sending SYNC_UL and waiting for RTT, and detect the timed message of whether receiving on rapid physical Acquisition Indicator Channel FPACH in N descending sub frame of setting quantity subsequently; Amending unit when being used for determining to receive timed message, according to the time deviation modified R TT in timed message, and is adjusted sub-frame of uplink and descending sub frame starting point according to revised RTT; Response unit, terminal interval 2 or 3 sub-frame of uplink after receiving timed message after being used for adjusting send Random Access Channel RACH message on the corresponding Physical Random Access Channel PRACH of FPACH.

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

The present invention is that reference is described according to flow chart and/or the block diagram of method, equipment (system) and the computer program of the embodiment of the present invention.Should understand can be by the flow process in each flow process in computer program instructions realization flow figure and/or block diagram and/or square frame and flow chart and/or 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 realizing in the function of 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 realized 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 be provided for realizing 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 in the instruction of carrying out on computer or other programmable devices.

Although described the preferred embodiments of the present invention, in a single day those skilled in the art get the basic creative concept of cicada, 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 and not break away from the spirit and scope of the present invention the present invention.Like this, if within of the present invention these are revised and modification belongs to the scope of claim of the present invention and equivalent technologies thereof, the present invention also is intended to comprise these changes and modification interior.

Claims

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

2. the method for claim 1, it is characterized in that, in the method, FDD is adopted in terminal and base station, 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 that for the uplink pilot time slot UpPTS of uplink synchronous with for the uplink service time slot that transmits uplink user data, described descending sub frame comprises for the down link pilot timeslot DwPTS of down-going synchronous with for 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. described method as arbitrary in claim 1 ~ 4, is characterized in that, terminal also comprises after sending SYNC_UL:

6. method as claimed in claim 5, is characterized in that, described N is 4, if the length of the RACH message that sends is greater than 1, and the subframe numbers of receiving the descending sub frame of timed message is odd number, and 3, interval sub-frame of uplink sends RACH message, otherwise 2, interval sub-frame of uplink sends RACH message.

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

8. described method as arbitrary in claim 2 ~ 4, it is characterized in that, in the method, terminal determines on 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 of the leading descending sub frame of 0ms=＜sub-frame of uplink＜subframe lengths T.

9. method as claimed in claim 8, is characterized in that, in the method, terminal determines that the method for next sub-frame of uplink/descending sub frame is:

10. described method as arbitrary in claim 1 ~ 4, is characterized in that, the division of residential quarter makes the one way propagation delay inequality of all terminals in same residential quarter in subframe lengths T.

11. method as claimed in claim 10 is characterized in that, the division of residential quarter makes the one way propagation time delay of all terminals in the residential quarter to the T remainder, and the terminal of remainder in T/2 be a residential quarter, remainder at T/2 to the terminal between T in the another one residential quarter.

12. method as claimed in claim 10 is characterized in that, the division of residential quarter is not more than the one way propagation delay inequality of all terminals in the residential quarter and sends 1/2 of SYNC_UL permission jitter range.

13. method as claimed in claim 12 is characterized in that, described transmission SYNC_UL allows jitter range by the number of chips of the Time Slot Occupancy that allows transmission SYNC_UL in sub-frame of uplink, deducts the shared number of chips of SYNC_UL transmission and determines.

14. method as claimed in claim 13 is characterized in that, the time slot that described permission sends SYNC_UL is UpPTS, or is 1 uplink service time slot after UpPTS+UpPTS, or is 2 uplink service time slots after UpPTS+UpPTS.

15. method as claimed in claim 12, 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 residential quarter is not more than 1/2 of transmission SYNC_UL permission jitter range.

16. the terminal of the random access of the carrying out under a long time delay is characterized in that, comprising:

17. terminal as claimed in claim 16, it is characterized in that, each unit in 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 that for the uplink pilot time slot UpPTS of uplink synchronous with for the uplink service time slot that transmits uplink user data, described descending sub frame comprises for the down link pilot timeslot DwPTS of down-going synchronous with for the downlink business time slot that transmits down user data.

18. terminal as claimed in claim 17, it is characterized in that, each unit in 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 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.

19. described terminal as arbitrary in claim 16 ~ 18 is characterized in that, also comprises:

20. described terminal as arbitrary in claim 16 ~ 18, 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 residential quarter, place, base station.

21. terminal as described in claim 17 or 18 is characterized in that, also comprises:

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

22. terminal as claimed in claim 16 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 same subframe is next sub-frame of uplink/descending sub frame.

23. described terminal as arbitrary in claim 16 ~ 18 is characterized in that in residential quarter, described terminal place, the one way propagation delay inequality of all terminals is in subframe lengths T.

24. terminal as claimed in claim 23 is characterized in that, in residential quarter, described terminal place, the one way propagation time delay of all terminals is to the T remainder, and the terminal of remainder in T/2 be a residential quarter, remainder at T/2 to the terminal between T in the another one residential quarter.

25. terminal as claimed in claim 23 is characterized in that, in residential quarter, described terminal place, the one way propagation delay inequality of all terminals is not more than and sends 1/2 of SYNC_UL permission jitter range.