CN103517397B - A kind of method of periodic empty synchronization and base station - Google Patents
A kind of method of periodic empty synchronization and base station Download PDFInfo
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Abstract
The present invention, which provides a kind of method of periodic empty synchronization and base station, this method, to be included：Base station carry out air interface synchronization when, when judge object synchronization base station for macro station or it is non-synchronous base station is completed in a manner of air interface synchronization when, in each one synchronous subframe of synchronized cyclic scheduling；When judging that synchronous base station is completed in object synchronization base station for air interface synchronization mode, in the descending silent subframe of each synchronized cyclic scheduling one and a synchronous subframe；The OFDM symbol of the synchronous subframe and the descending silent subframe is planned, selects suitable OFDM symbol to be used to send downlink control channel.Normal traffic scheduling can be influenceed reduction when Femto base stations carry out periodic empty synchronization according to the present invention.
Description
Technical field
The present invention relates to field of wireless communication, and in particular to the cycle influenceed on traffic scheduling is reduced in a kind of LTE system
The method of air interface synchronization and base station.
Background technology
LTE (Long Term Evolution, Long Term Evolution) Femto families level base station (HeNB) technology is that solve at present
One of important technology of LTE in-door coverings, have the characteristics that networking high efficient and flexible, cost are cheap.By in signal blind spot region
Femto base stations are disposed, can easily improve the network coverage, network capacity is lifted, mitigates the traffic pressure of macro station, carried for user
Experienced for better services, there is obvious networking advantage.
LTE system includes FDD (Frequence Division Duplex, FDD) and TDD (Time Division
Duplex, time division duplex) two kinds of duplex modes.FD-LTE is by different frequency range division up-downgoings, in a 10ms radio frames
10 1ms subframes can carry out up-downgoing business transmission simultaneously；TD-LTE divides up-downgoing by different time slots, according to
Mode is matched according to different up-downgoing, by 10 1ms sub-frame divisions in a 10ms radio frames is sub-frame of uplink (U), descending
Subframe (D) and special subframe (S).7 kinds of TDD different up-downgoings proportioning mode, the up-downgoing of different ratio are defined in agreement
Subframe ratio is different, can meet the different up-downgoing traffic demands of different business application scenarios.
In order to correct detected wireless signals, avoid disturbing, LTE system requires keep frequency and time between each base station
It is synchronous.Especially, due to relying on the division of accurate time slot to carry out differentiating uplink and downlink under tdd mode, therefore time accuracy is wanted
Ask higher, it is desirable to strict time synchronized must be kept between each base station, otherwise serious adjacent area will be brought to disturb.Need
It is bright, if do not dispose eMBMS (Evolved Multimedia Broadcast and Multicast Service,
Evolution type multimedia broadcast and multicast service) or eICIC (Evolved Inter-Cell Interference
Coordination, evolved Inter-Cell Interference Coordination) ABS (Almost Blank Subframe, almost blank subframe) work(
Can, FDD can not need time synchronized, it is only necessary to Frequency Synchronization.
Realize that synchronous method mainly has GPS (Global Positioning System, the whole world in LTE system at present
Alignment system), 1588v2 and air interface synchronization.GPS and 1588v2 there are certain requirements for deployed environment, for Femto base stations
For, it is not easy to obtain gps signal due to major deployments indoors, and in view of the Cost Problems of Home eNodeB, Femto bases
GPS device may not had by standing, it is also possible to be inconvenient to dispose 1588v2 networks, therefore air interface synchronization shows for Femto base stations
Obtain particularly important.When the environment residing for Femto base stations and macro station or other Femto base stations have covering overlapping, Femto base stations are just
Target BS that can be using macro station or other Femto base stations as air interface synchronization, using the main and auxiliary synchronizing signal of target BS with
And descending cell reference signals realize synchronization, so as to reducing inter-cell interference.
Air interface synchronization process is divided into initial synchronisation and cycle synchronisation.Initial synchronisation completes initially setting up for air interface synchronization
Journey, including the selection of object synchronization base station, the acquisition of frame number and initial when frequency deviation are synchronous.Initial synchronization detection object synchronization base
The PSS (Primary Synchronization Signal, master sync signal) and SSS (Secondary to stand
Synchronization Signal, auxiliary synchronous signals) calculated, operand is very big, general only in search object synchronization base
Used when standing.
Cycle synchronisation carries out the when frequency deviation tracking adjustment in cycle on the basis of air interface synchronization foundation.Cycle synchronisation is typically logical
Cross descending CRS (Common Reference Signal, public reference signal, i.e. the descending pilot frequency letter of detection object synchronization base station
Number) to carry out when frequency offset calculation.
Femto base stations need to interrupt normal up-downgoing business transmission in period tracking air interface synchronization signal, can adjust
One special function subframe of degree uses as air interface synchronization, hereinafter referred to as synchronous subframe.In the 1ms time slots of this subframe
It is interior, the descending CRS signals of Femto base stations reception target BS, the associative operation of execution cycle synchronization, therefore in a tdd system,
Synchronous subframe is necessary for descending sub frame.
When Femto base stations are not in the coverage of macro station signal, one can be chosen and completed synchronous Femto
Neighboring station is as its object synchronization base station.Assuming that the neighboring station is synchronized to macro station using the mode of air interface synchronization, 2 layers are now formd
The synchronized relation of level.When downstream signal of the neighboring station in its synchronous subframe moment detection macro station, the now descending transmission of this base station
Interference will be produced to it.In the air interface synchronization of multi-layer, cooperation silence mode as shown in Figure 1 is typically taken to avoid above-mentioned dry
Disturb.Specific practice is：At the time of HeNB1 schedule synchronization subframes, HeNB2 correspondingly dispatches a descending silent subframe and is used to assist
Make silence, stop descending transmission at the subframe moment, to avoid the air interface synchronization operation to HeNB1 from producing interference.Dispatching downlink
After silent subframe, HeNB2 dispatches a synchronous subframe again, completes the air interface synchronization operation of itself.Covered in view of wireless signal
Scope, in the air interface synchronization of more levels, base station can also only dispatch a descending silent subframe, so that it may meet to interference
Evade requirement.
The synchronous subframe moment is used for the downstream signal for detecting object synchronization base station, it is impossible to carries out normal up-downgoing business and adjusts
Spend, equivalent to one blank subframe for the UE (User Equipment, user equipment) for accessing this base station.In addition,
In the air interface synchronization of multi-layer, descending silent subframe equivalent to one descending blank subframe for the UE for accessing this base station.
Analyzed below mainly in combination with synchronous subframe, influence of the descending silent subframe to scheduling can be considered shadow of the synchronous subframe to scheduling
Loud a subset.
Because the handling processes such as LTE up-downgoing traffic scheduling, feedback, re-transmission have strict timing requirements, blank subframe
Introducing normal traffic scheduling flow belt can be given to influence, be in particular in the transmitting-receiving to downlink control channel, and
In influence to up-downgoing HARQ (Hybrid Automatic Repeat Request, hybrid automatic request retransmit) sequential.
Position of the LTE downlink control channels in descending sub frame is as shown in Fig. 2 including following physical channel：
PCFICH (Physical Control Format Indicator Channel, Physical Control Format Indicator Channel), PDCCH
(Physical Downlink Control Channel, Physical Downlink Control Channel) and PHICH (Physical Hybrid
ARQ Indicator Channel, Physical HARQ Indicator Channel).
PCFICH carries a CFI (Control Format Indicator, control format instruction), represents each subframe
It is middle send downlink control channel OFDM (Orthogonal Frequency Division Multiplexing, it is orthogonal
Frequency division multiplexing) symbolic number.CFI value is usually 1,2,3,4.
The information that PDCCH is carried is referred to as DCI (Downlink Control Information, downlink control letter
Breath), it includes resource allocation and one or one group UE other control information.Different DCI message formats have difference in functionality.
DCI format 0 is used to carry out PUSCH (Physical Uplink Shared Channel, Physical Uplink Shared Channel) resource
Authorize, DCI format 3/3A is used for transmission power control command, and other DCI formats are used for carrying out the PDSCH under different situations
(Physical Downlink Shared Channel, Physical Downlink Shared Channel) distributes.
PHICH carries HARQ ACK/NACK, and whether instruction base station has correctly received PUSCH transmission.
For LTE up-downgoings data transfer based on the scheduling of HARQ processes, scheduler is located at MAC (the media accesses of base station
Control) layer, its function is for downstream transmission channel distribution physical layer resources, shared resource is fully used.According to
Whether the time-domain position of HARQ processes is fixed, and can be divided into synchronous HARQ and asynchronous HARQ：
Synchronous HARQ：The time domain of each HARQ processes is limited in the pre- position set, each HARQ process schedulings moment
Fixed to the interval at feedback moment, the feedback moment is also fixed to the interval of scheduling instance next time.The up of LTE is synchronous
HARQ。
Asynchronous HARQ：One HARQ process can occur in any subframe, can more neatly distribute HARQ resources, but
It is to need extra signaling to indicate the subframe where each HARQ processes.Each HARQ process scheduling moment is to feeding back time at intervals
Fixed, the feedback moment is not fixed to scheduling instance interval next time.The descending of LTE is asynchronous HARQ.
Whether need PDCCH indicate, can be divided into adaptive HARQ and non-self-adapting HARQ if being retransmitted according to HARQ：
Adaptive HARQ：Scheduler adjusts RB (Resource Block, the money for retransmitting use every time according to channel condition
Source block), the parameter such as MCS (Modulation and Coding Scheme, modulation coding mode) is, it is necessary to which PDCCH is indicated.LTE
It is up can use adaptive HARQ, it is descending to use adaptive HARQ.
Non-self-adapting HARQ：There is no PDCCH instructions, using RB, MCS parameter being transmitted with last time.Only referred to by PHICH
Show that ACK (confirmation) or NACK triggerings (unconfirmed) retransmit.The up of LTE can use non-self-adapting HARQ.
For downlink data transmission, base station is provided in row subframe by PDCCH to UE dynamically distributes downlink transfer in each of the lower
Source TB (Transport Block, transmission block), and notify corresponding HARQ process messages.There is a descending HARQ entity UE sides,
For managing a series of parallel HARQ processes, each process is identified by its process number.
After UE receives TB and correlation HARQ process messages, HARQ processes do following judgement：If in HARQ processes
NDI (New Data Indicator, new data indicator) value of offer is overturn, then is currently sent for new data；It is no
Then sent to retransmit data.
UE is according to new biography or the decoding cases of re-transmission, and generation ACK/NACK message feedbacks are to base station.Descending HARQ feedback and
Retransmission time is controlled according to different dual-mode and ratio of uplink subframe to downlink subframe by respective specific sequential.
For transmitting uplink data, UE is data sending terminal, and scheduler is located at base station.Ascending resource is distributed with dynamic dispatching
Based on, under non-DRX (Discontinuous Reception, discontinuous to receive) state, UE in each subframe by detecting
PDCCH determines whether the ascending resource mandate for the UE.There is an ascending HARQ entity UE sides, a series of for managing
Parallel HARQ processes, so as to which other data can be continuously transmitted during the transmission feedback before wait.
If receiving the ascending resource mandate of the instructions of DCI 0 in present sub-frame, HARQ entities can determine one according to sequential
HARQ processes are used to send data, afterwards the HARQ processes by etc. ACK/NACK feedbacks transmit in PHICH of base station to be received.
NACK is fed back to if receiving, in not up to up maximum transmission times, UE will trigger up non-self-adapting weight
Pass.Up non-self-adapting retransmission time is entered according to different dual-mode and ratio of uplink subframe to downlink subframe by respective specific sequential
Row control, it is not necessary to authorized according to DCI 0 to indicate to retransmit.
If not receiving NACK feedbacks, the state that now the HARQ processes are likely to be at includes：New biography success, HARQ processes
Hang up or wait adaptive retransmission.Whether transmission before, which retransmits, needs to indicate that UE sides still retain what is sent before by NDI values
Data buffer zone.Only when the DCI 0 for receiving the upset of NDI values is indicated, UE just carries out new biography and updates the data buffering area, otherwise
Carry out the adaptive retransmission that DCI 0 is indicated.
Analysis understands that LTE up-downgoing data transfer is by strict SECO, wherein downlink control more than
The effect of channel processed is particularly important, not only carries out downlink transfer resource allocation, ascending resource mandate on this channel, while go back shadow
Ring the handling process of ascending HARQ.If the introducing of synchronous subframe or descending silent subframe causes downlink control channel to lack
Lose, considerable influence will be produced to whole LTE traffic schedulings flow.
The content of the invention
The technical problem to be solved in the present invention is to provide a kind of method of periodic empty synchronization and base station, to be carried out in base station
Reduced during periodic empty synchronization influences on normal traffic scheduling.
In order to solve the above-mentioned technical problem, the invention provides a kind of method of periodic empty synchronization, including：
When base station carries out air interface synchronization, when judging object synchronization base station for macro station or non-synchronization completed in a manner of air interface synchronization
Base station when, in each one synchronous subframe of synchronized cyclic scheduling；When judging that object synchronization base station completes for air interface synchronization mode
During the base station of synchronization, in the descending silent subframe of each synchronized cyclic scheduling one and a synchronous subframe；
The OFDM symbol of the synchronous subframe and the descending silent subframe is planned, selects suitable orthogonal frequency
Multiplexed symbols are divided to be used to send downlink control channel.
Further, the above method also has following feature：For planning that the OFDM of the synchronous subframe accords with
Number, select suitable OFDM symbol to include：
OFDM symbol 0；Or
OFDM symbol 0 and 1；Or
OFDM symbol 0,1 and 2；Or
OFDM symbol 0,1,2 and 3.
Further, the above method also has following feature：Orthogonal frequency division multiplexing for planning the descending silent subframe
With symbol, suitable OFDM symbol is selected to include：
Selection and upper strata object synchronization base station synchronous subframe is planned for sending the orthogonal of downlink control channel
Frequency division multiplexing symbol identical OFDM symbol.
Further, the above method also has following feature：During the base station carries out air interface synchronization, in addition to：
If confirming, system dual-mode be time division duplex, stop the synchronous subframe carry out descending new biography scheduling with it is descending
Retransfer scheduling；
If confirming, system dual-mode is FDD, is stopped when the synchronous subframe shifts to an earlier date 4 subframes up new
Teach power；Synchronous subframe will appear from uplink retransmission as described in judging, then will be up heavy when the synchronous subframe shifts to an earlier date 4 subframes
Pass and hang up；Stop the synchronous subframe and carry out descending new biography scheduling and descending retransfer scheduling.
Further, the above method also has following feature：During the base station carries out air interface synchronization, in addition to：
Stop the descending silent subframe and carry out descending new biography scheduling and descending retransfer scheduling.
In order to solve the above problems, present invention also offers a kind of base station, including：
First module, during for carrying out air interface synchronization, when judging object synchronization base station for macro station or non-with air interface synchronization side
When formula completes synchronous base station, in each one synchronous subframe of synchronized cyclic scheduling；It is same to eat dishes without rice or wine when judging object synchronization base station
When step mode completes synchronous base station, in the descending silent subframe of each synchronized cyclic scheduling one and a synchronous subframe；
Second module, for planning the OFDM symbol of the synchronous subframe and the descending silent subframe, choosing
Suitable OFDM symbol is selected to be used to send downlink control channel.
Further, above-mentioned base station also has following feature：Second module is for planning the synchronous subframe just
Frequency division multiplexing symbol is handed over, selects suitable OFDM symbol to include：
OFDM symbol 0；Or
OFDM symbol 0 and 1；Or
OFDM symbol 0,1 and 2；Or
OFDM symbol 0,1,2 and 3.
Further, above-mentioned base station also has following feature：
Second module, the OFDM symbol for planning the descending silent subframe, selection are suitable just
Frequency division multiplexing symbol is handed over to include：Selection and upper strata object synchronization base station synchronous subframe is planned for sending downlink control
The OFDM symbol identical OFDM symbol of channel.
Further, above-mentioned base station also has following feature：Also include：
3rd module, if for confirming that system dual-mode is time division duplex, it is descending to stop the synchronous subframe progress
New biography is dispatched and descending retransfer scheduling；
4th module, if for confirming that system dual-mode is FDD, shift to an earlier date 4 subframes in the synchronous subframe
When stop up new biography mandate；Synchronous subframe will appear from uplink retransmission as described in judging, then shifts to an earlier date 4 sons in the synchronous subframe
Uplink retransmission is hung up during frame；Stop the synchronous subframe and carry out descending new biography scheduling and descending retransfer scheduling.
Further, above-mentioned base station also has following feature：Also include：
5th module, descending new biography scheduling and descending retransfer scheduling are carried out for stopping the descending silent subframe.
To sum up, the present invention provides method and the base station of a kind of periodic empty synchronization, and it is empty can to carry out the cycle in Femto base stations
Reduced when mouth is synchronous influences on normal traffic scheduling.
Brief description of the drawings
Cooperation silence schematic diagram when Fig. 1 is multi-layer air interface synchronization；
Fig. 2 is the time-frequency region schematic diagram of descending sub frame；
Fig. 3 is the flow chart of the method for the periodic empty synchronization of the embodiment of the present invention；
Fig. 4 is the planning schematic diagram of the synchronous subframe and descending silent subframe in the embodiment of the present invention；
Fig. 5 is the flow chart that the present invention applies the periodic empty synchronization in example；
Fig. 6 is the schematic diagram of the base station of the embodiment of the present invention.
Embodiment
For the object, technical solutions and advantages of the present invention are more clearly understood, below in conjunction with accompanying drawing to the present invention
Embodiment be described in detail.It should be noted that in the case where not conflicting, in the embodiment and embodiment in the application
Feature can mutually be combined.
Fig. 3 is the flow chart of the method for the periodic empty synchronization of the embodiment of the present invention, as shown in figure 3, comprising the following steps：
Step 11, when base station carries out air interface synchronization, when judging object synchronization base station for macro station or non-in a manner of air interface synchronization
When completing synchronous base station, in each one synchronous subframe of synchronized cyclic scheduling；When judging object synchronization base station for air interface synchronization
When mode completes synchronous base station, in the descending silent subframe of each synchronized cyclic scheduling one and a synchronous subframe；
Step 12, the OFDM symbol of the synchronous subframe and the descending silent subframe is planned, selection is properly
OFDM symbol be used for send downlink control channel.
Further, including step 13, to the synchronous subframe and the descending silent subframe, distinguish duplex mode and carry out
Different dispatch deals, evade the influence to normal up-downgoing HARQ sequential.
For the synchronous subframe, suitable OFDM symbol number is selected to be used to send downlink control letter
Road, and be the enough OFDM symbol numbers of radio frequency up-downgoing handoff reservation；For the descending silent subframe, according to
Planning of the upper strata object synchronization base station to synchronous subframe, identical OFDM symbol number is selected to be used to send descending chain
Road control channel.
Base station can make rational planning for the time of descending silent subframe and synchronous subframe process cycle air interface synchronization, be descending chain
The transmission of road control channel creates conditions, to ensure on the premise of execution cycle synchronization process demand, to meet descending chain as far as possible
The transmission demand of road control channel, avoid impacting uplink feedback and uplink authorization sequential.
In order to send downlink control channel, it is easy to radio frequency to switch again, considers the processing delay of cycle synchronisation,
And the processing delay of radio frequency up-downgoing switching, classifying rationally, choosing are carried out to 14 OFDM symbols that a synchronous subframe takes
Select fixed CFI values.In the present embodiment, OFDM symbol 0 can be selected to be used to send downlink control channel, then CFI takes
It is worth for 1；OFDM symbol 0 and 1 can be selected, then CFI values are 2；OFDM symbol 0,1 and 2 can be selected, then CFI values are 3；
OFDM symbol 0,1,2 and 3 can also be selected, then CFI values are 4 etc..
In cycle synchronisation, offset estimation value can be obtained by carrying out frequency domain correlation computations by pilot channel estimation, be realized
Frequency Synchronization；Time synchronized can be realized using the time domain correlation of frequency pilot sign.
As shown in Fig. 2 on a descending sub frame, down-bound pilot frequency signal is distributed with OFDM symbol 0,7,4,11, can be with
Choose the down-bound pilot frequency signal combination with different correlated performances and carry out correlation computations, including：
0,7,4,11 liang of pairwise correlations of symbol；
Symbol 0,4 is related；
Symbol 0,7 is related；
Symbol 4,7 is related；
Symbol 4,11 is related；
Symbol 7,11 is related.
In view of the transmission requirement of downlink control channel, correlation computations are carried out without using symbol 0.Estimated according to different
Scope and accuracy requirement are counted, symbol 4 can be selected related to 7, symbol 4 is related to 11, or these three groups related to 11 of symbol 7
Close.In the present embodiment, correlation computations are carried out using symbol 4 and 11, as shown in figure 4, Femto base stations need to arrive symbol in symbol 4
The down-bound pilot frequency signal of detection object synchronization base station, continues 8 OFDM symbol times altogether during 11.
In the present embodiment, such as the radio frequency up-downgoing handover delay duration is about 2 OFDM symbol length.
14 OFDM symbols where synchronous subframe are made with following planning：
Symbol 0,1 moment, downlink control channel is sent, i.e., fixed CFI is 2；
Symbol 2,3 moment, radio frequency switch to uplink receiving state by descending transmission, to receive the descending of object synchronization base station
Pilot signal is prepared；
Symbol 4 receives the down-bound pilot frequency signal of object synchronization base station, performs periodic empty synchronization behaviour to the moment of symbol 11
Make；
Symbol 12,13 moment, radio frequency switch back into normal descending transmission state by uplink receiving.
In view of not having downlink service data scheduling in synchronous subframe, PDCCH only needs to send to be awarded to UE uplink scheduling
Power, therefore the downlink control channel of 2 symbols can meet the transmission of PCFICH, PDCCH and PHICH in most cases
Demand.
In the present embodiment, if needing dispatching downlink silence subframe, the planning to descending silent subframe as shown in Figure 4, it is necessary to
The synchronous subframe of base station synchronous with upper strata chooses identical CFI values, selects symbol 0 and 1 to be used to send downlink control letter
Road.Descending silent subframe does not need radio frequency switching, it is not necessary to reserved switching time.
In FDD system, the up no business of synchronous subframe, descending sends the downlink control channel that CFI is 2；TDD
In system, synchronous subframe only sends the downlink control channel that CFI is 2.
Because the occupancy of synchronous subframe reduces the number of sub-frames for regular traffic transmission, up-downgoing business HARQ sequential
It can be affected, it is also necessary to do the special dispatch deal of a step on this basis.Concrete analysis is as follows：
In a tdd system, due to including the schedule information DCI0 of sub-frame of uplink in PDCCH, and can obtain on PHICH
The HARQ feedback information of carrying, it is believed that uplink service scheduling is unaffected.The new biography of downlink business and re-transmission can be because same
The setting of step frame and postpone, due to it is descending be asynchronous HARQ, retransmission time can put off backward.
In FDD system, the up-downgoing traffic scheduling during air interface synchronization can be skipped：
(1) for FDD uplink services, it is unaffected in the uplink HARQ feedback of PHICH carryings, simply up heavy
Passing the moment may be taken by synchronous subframe.Due to it is up be synchronous HARQ, no matter using adaptive retransmission or it is non-from
Adapt to retransmit, retransmission time is fixed.Here with the re-transmission suspending mechanism of ascending HARQ, force to all estimated same
The UE that feedback is obtained on step frame sends ACK, and the UE retransmitted to needs is put into retransmission queue, waits DCI0 to be sent to carry out adaptive
Retransmit.Because UE does not refresh transmission buffering area, when the DCI0 instructions that one NDI of subsequent base stations transmission is not overturn, actually will
Adaptive retransmission is carried out to the ascending HARQ of hang-up.
(2) for FDD downlink business, when being taken by synchronous subframe at the feedback moment, there can be two kinds of processing modes：
The business of descending scheduling is retransmitted, or predicted can not be fed back in the case of without descending scheduling.The
A kind of benefit of mode is that UE sides can carry out re-transmission merging；The benefit of the second way is to be not required to send out at synchronous subframe moment UE
HARQ feedback is sent, can save energy and reduce the interference to adjacent area.
In the air interface synchronization of multi-layer, also need to consider the influence brought during cooperation is silent.Performed in last layer HeNB
During air interface synchronization, this layer of HeNB need to keep descending silence, and wherein FDD and TDD down control channel are transmittable, and CFI is solid
Fixed, PDSCH is not sent；FDD up processing should be unaffected during cooperation is silent.Cooperation quiet period dispatches this layer after terminating
Synchronous subframe corresponding to HeNB.
It can obtain more than on the premise of ensureing that downlink control channel is normally sent, air interface synchronization is to HARQ sequential
Influence as follows：
(1) TDD system is substantially unaffected, it is only necessary to is ensured in descending silent subframe and synchronous subframe without descending
Traffic scheduling；
(2) it is consistent with TDD system for descending silent subframe, the operation of FDD system；For synchronous subframe, FDD system is removed
Need to ensure in synchronous subframe do not have outside uplink and downlink business, it is also necessary to consider anti-to uplink and downlink business scheduled before
The processing of feedback.
Analyzed with reference to more than, it is reasonable that the embodiment of the present invention is carried out in the OFDM symbol to descending silent subframe and synchronous subframe
Division, on the basis of ensureing that downlink control channel is normally sent, it is also necessary to which special place is carried out to up-downgoing traffic scheduling
Reason, further to reduce influence of the air interface synchronization to up-downgoing HARQ sequential, as shown in figure 5, mainly including the following steps that：
Step 101：Confirm the air interface synchronization level of this base station.
Step 102：When level be 1, i.e., object synchronization base station be macro station or it is other do not use air interface synchronization base station when,
One synchronous subframe of each synchronized cyclic scheduling；When level is more than 1, i.e., when object synchronization base station also performs air interface synchronization, it is necessary to
The synchronous subframe position of last layer base station is confirmed as to the descending silent subframe position of this base station, and dispatch this base station one is same
Step frame.
Step 103：The symbol of synchronous subframe and descending silent subframe is made rational planning for；
Step 104：To the special dispatch deal of descending silent subframe, including：
Confirm descending silent subframe position s；
Stop subframe s descending new biography scheduling and descending retransfer scheduling.
Processing does not differentiate between duplex mode above.
Step 105, to the special dispatch deal of synchronous subframe, including：
Confirm synchronous subframe position k；
Confirmation system dual-mode：
In this way during TDD system, subframe k stops descending new biography scheduling and descending retransfer scheduling；
In this way, it is necessary to carry out following handle during FDD system：
Stop the uplink service of the subframe k, i.e., stop newly teaching the up of the synchronous subframe in subframe (k-4)
Power；
If subframe k will appear from uplink retransmission, uplink retransmission is hung up in advance in subframe (k-4)；
Stop subframe k descending new biography scheduling and descending retransfer scheduling.
Fig. 6 is the schematic diagram of the base station of the embodiment of the present invention, as shown in fig. 6, the base station of the present embodiment includes：
First module, during for carrying out air interface synchronization, when judging object synchronization base station for macro station or other non-air interface synchronizations
During base station, in each one synchronous subframe of synchronized cyclic scheduling；When judge object synchronization base station also using air interface synchronization mode it is complete
Into it is synchronous when, in the descending silent subframe of each synchronized cyclic scheduling one and a synchronous subframe；
Second module, for planning the OFDM symbol of the synchronous subframe and the descending silent subframe, choosing
Suitable OFDM symbol is selected to be used to send downlink control channel.
Wherein, second module is for the OFDM symbol of the planning synchronous subframe, and selection is suitably just
Frequency division multiplexing symbol is handed over to include：
OFDM symbol 0；Or
OFDM symbol 0 and 1；Or
OFDM symbol 0,1 and 2；Or
OFDM symbol 0,1,2 and 3.
Wherein, for the OFDM symbol of the planning descending silent subframe, suitable orthogonal frequency division multiplexing is selected
Included with symbol：Selection and upper strata object synchronization base station synchronous subframe is planned for sending downlink control channel just
Hand over frequency division multiplexing symbol identical OFDM symbol.
In a preferred embodiment, the base station can also include：
3rd module, if for confirming that system dual-mode is time division duplex, it is descending to stop the synchronous subframe progress
New biography is dispatched and descending retransfer scheduling；
4th module, if for confirming that system dual-mode is FDD, in synchronous 4 subframes of subframe described in advance
When stop up new biography mandate；Synchronous subframe will appear from uplink retransmission as described in judging, then in synchronous 4 sons of subframe described in advance
Uplink retransmission is hung up during frame；Stop the synchronous subframe and carry out descending new biography scheduling and descending retransfer scheduling.
In a preferred embodiment, the base station can also include：
5th module, descending new biography scheduling and descending retransfer scheduling are carried out for stopping the descending silent subframe.
When Femto base stations carry out periodic empty synchronization, the introducing of descending silent subframe and synchronous subframe reduces and can carried out
The number of sub-frames of regular traffic scheduling, can be impacted to normal HARQ sequential.The periodic empty synchronization of the embodiment of the present invention
Method and base station, suitable for TDD and FDD system.This method passes through the reasonable rule to the Base-Band Processing periodic empty synchronization time
Draw, and the radio frequency up-downgoing switching carved in due course, descending silent subframe and synchronous subframe downlink control can not be influenceed
The transmission of channel processed；Further, by appropriate dispatch deal, descending silent subframe can be evaded and synchronous subframe aligns
The influence of normal up-downgoing business.
One of ordinary skill in the art will appreciate that all or part of step in the above method can be instructed by program
Related hardware is completed, and described program can be stored in computer-readable recording medium, such as read-only storage, disk or CD
Deng.Alternatively, all or part of step of above-described embodiment can also be realized using one or more integrated circuits.Accordingly
Ground, each module/unit in above-described embodiment can be realized in the form of hardware, can also use the shape of software function module
Formula is realized.The present invention is not restricted to the combination of the hardware and software of any particular form.
The preferred embodiments of the present invention are these are only, certainly, the present invention can also there are other various embodiments, without departing substantially from this
In the case of spirit and its essence, those skilled in the art work as can make various corresponding changes according to the present invention
And deformation, but these corresponding changes and deformation should all belong to the protection domain of appended claims of the invention.
Claims (8)
1. a kind of method of periodic empty synchronization, including：
When base station carries out air interface synchronization, when judging object synchronization base station for macro station or non-synchronous base completed in a manner of air interface synchronization
When standing, in each one synchronous subframe of synchronized cyclic scheduling；When judging that object synchronization base station completes synchronization for air interface synchronization mode
Base station when, in the descending silent subframe of each synchronized cyclic scheduling one and a synchronous subframe；
The OFDM symbol of the synchronous subframe and the descending silent subframe is planned, selects suitable orthogonal frequency division multiplexing
It is used to send downlink control channel with symbol；
During the base station carries out air interface synchronization, in addition to：
Stop the descending silent subframe and carry out descending new biography scheduling and descending retransfer scheduling.
2. the method as described in claim 1, it is characterised in that：For planning that the OFDM of the synchronous subframe accords with
Number, select suitable OFDM symbol to include：
OFDM symbol 0；Or
OFDM symbol 0 and 1；Or
OFDM symbol 0,1 and 2；Or
OFDM symbol 0,1,2 and 3.
3. the method as described in claim 1, it is characterised in that：OFDM for planning the descending silent subframe
Symbol, suitable OFDM symbol is selected to include：
Select the orthogonal frequency for being used to send downlink control channel planned with upper strata object synchronization base station synchronous subframe
Multiplexed symbols identical OFDM symbol.
4. the method as described in claim any one of 1-3, it is characterised in that：During the base station carries out air interface synchronization,
Also include：
If confirming, system dual-mode is time division duplex, stops the synchronous subframe and carries out descending new biography scheduling and descending re-transmission
Scheduling；
If confirming, system dual-mode is FDD, stops up newly teaching when the synchronous subframe shifts to an earlier date 4 subframes
Power；Synchronous subframe will appear from uplink retransmission as described in judging, then hangs uplink retransmission when the synchronous subframe shifts to an earlier date 4 subframes
Rise；Stop the synchronous subframe and carry out descending new biography scheduling and descending retransfer scheduling.
5. a kind of base station, including：
First module, during for carrying out air interface synchronization, when judge object synchronization base station for macro station or it is non-in a manner of air interface synchronization it is complete
During into synchronous base station, in each one synchronous subframe of synchronized cyclic scheduling；When judging object synchronization base station for air interface synchronization side
When formula completes synchronous base station, in the descending silent subframe of each synchronized cyclic scheduling one and a synchronous subframe；
Second module, for planning the OFDM symbol of the synchronous subframe and the descending silent subframe, selection is closed
Suitable OFDM symbol is used to send downlink control channel；
Also include：
5th module, descending new biography scheduling and descending retransfer scheduling are carried out for stopping the descending silent subframe.
6. base station as claimed in claim 5, it is characterised in that：Second module is for planning the orthogonal of the synchronous subframe
Frequency division multiplexing symbol, suitable OFDM symbol is selected to include：
OFDM symbol 0；Or
OFDM symbol 0 and 1；Or
OFDM symbol 0,1 and 2；Or
OFDM symbol 0,1,2 and 3.
7. base station as claimed in claim 5, it is characterised in that：
Second module, the OFDM symbol for planning the descending silent subframe, selects suitable orthogonal frequency
Multiplexed symbols are divided to include：Selection and upper strata object synchronization base station synchronous subframe is planned for sending downlink control channel
OFDM symbol identical OFDM symbol.
8. the base station as described in claim any one of 5-7, it is characterised in that：Also include：
3rd module, if for confirming that system dual-mode is time division duplex, stop the synchronous subframe and carry out descending new biography
Scheduling and descending retransfer scheduling；
4th module, if for confirming that system dual-mode is FDD, stop when the synchronous subframe shifts to an earlier date 4 subframes
Only up new biography mandate；Synchronous subframe will appear from uplink retransmission as described in judging, then when the synchronous subframe shifts to an earlier date 4 subframes
Uplink retransmission is hung up；Stop the synchronous subframe and carry out descending new biography scheduling and descending retransfer scheduling.
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| WO2014142628A2 (en) * | 2013-03-15 | 2014-09-18 | Lg Electronics Inc. | Method and apparatus for performing synchronization in wireless communication system |
| WO2016019515A1 (en) * | 2014-08-05 | 2016-02-11 | Nokia Solutions And Networks Oy | Controlling synchronization procedure of communication network control elements |
| CN104735774B (en) * | 2015-03-23 | 2018-05-01 | 京信通信系统（中国）有限公司 | A kind of air interface synchronization method and device based on networking |
| WO2017161583A1 (en) * | 2016-03-25 | 2017-09-28 | Intel IP Corporation | Method, apparatus and system for transmission acknowledgement control in a wireless network |
| CN111083781A (en) * | 2018-10-18 | 2020-04-28 | 普天信息技术有限公司 | Transmission method and device of PDCCH (physical Downlink control channel) information |
| CN111866792B (en) * | 2019-04-29 | 2021-12-17 | 大唐移动通信设备有限公司 | Signal sending and receiving method and terminal |
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| CN102014405A (en) * | 2009-12-24 | 2011-04-13 | 大唐移动通信设备有限公司 | Base station and synchronous processing method thereof in layered network |
| CN102160433A (en) * | 2008-09-19 | 2011-08-17 | 高通股份有限公司 | Synchronizing a base station in a wireless communication system |
| CN102202400A (en) * | 2011-05-31 | 2011-09-28 | 电信科学技术研究院 | Instruction and processing method and device for resource occupancy mode |
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| US8897235B2 (en) * | 2009-12-18 | 2014-11-25 | Qualcomm Incorporated | Protection of broadcast signals in heterogeneous networks |
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| CN102160433A (en) * | 2008-09-19 | 2011-08-17 | 高通股份有限公司 | Synchronizing a base station in a wireless communication system |
| CN102014405A (en) * | 2009-12-24 | 2011-04-13 | 大唐移动通信设备有限公司 | Base station and synchronous processing method thereof in layered network |
| CN102202400A (en) * | 2011-05-31 | 2011-09-28 | 电信科学技术研究院 | Instruction and processing method and device for resource occupancy mode |
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