CN1324824C - Mapping method for terminal synchronous control command in multiple time slot communication system - Google Patents

Abstract

The invention discloses a method for mapping terminal synchronization control commands in a multi-slot communication system. The method takes one subframe as the processing period and includes the following steps: the base station controller calculates the ULSC of the UE and the uplink time slot carrying the ULSC The position number in the uplink time slot occupied by the user terminal; according to the SS symbol mapping rule, the base station controller reversely calculates and obtains the SS symbol number in one or more downlink time slots corresponding to the uplink time slot number; according to the acquired The number of SS symbols configured by the UE in each downlink time slot it occupies, the base station controller calculates the downlink time slot where the SS symbol corresponding to the ULSC is located and the position of the SS symbol in the downlink time slot, and sends the ULSC to to the SS symbol position of the downlink slot. The invention realizes the downlink mapping of the uplink synchronization control command specified in the 3GPP protocol for UE maintenance and base station uplink synchronization, so that the SS symbol can be sent to the user terminal immediately in the next available downlink time slot.

Description

Mapping method of terminal synchronization control command in multi-slot communication system

technical field

The present invention relates to a method for synchronizing a user terminal (UE, User Equipment) and a base station (Node B) in a third-generation mobile communication system, and in particular to a method for mapping terminal synchronization control commands in a multi-slot communication system.

Background technique

In the third-generation mobile communication system, one of the core technologies of the TD-SCDMA (Time Division Duplex-Synchronous Code Division Multiplex Access) system is synchronous CDMA, especially between the user terminal and the base station. synchronization between. Using this synchronization technology can overcome the interference problem caused by non-orthogonal code channels in asynchronous CDMA because the code channel signals transmitted by each mobile terminal arrive at the base station at different times, thereby improving system capacity and spectrum utilization. The hardware circuit can be simplified and the cost can be reduced.

The synchronization between the user terminal and the base station in the TD-SCDMA system is divided into two parts: downlink synchronization and uplink synchronization. TD-SCDMA has a wireless frame length of 10ms, which can be divided into two 5ms subframes, and each subframe is divided into 7 regular time slots and 3 special time slots. The special time slots are downlink pilot time slot (DwPTS), guard interval (Gp) and uplink pilot time slot (UpPTS). The DwPTS in each subframe is designed for downlink pilot and downlink synchronization. This time slot is usually composed of a downlink synchronization code (SYNC_DL) with a length of 64 chips and a protection code interval of 32 chips. Maximum power is emitted in all directions or on a certain sector. After the UE is turned on, it must first establish downlink synchronization with the network through the downlink pilot time slot (DwPTS). Only when the downlink synchronization is established can the UE start to establish uplink synchronization. Since downlink synchronization is easy to implement, it is generally considered that downlink synchronization is stable when the system is working, and no special consideration is required.

The uplink synchronization between the user terminal and the base station is implemented in two steps: establishment of uplink synchronization and maintenance of uplink synchronization. The synchronization establishment uses the uplink pilot time slot (UpPTS) in the above subframe structure. This time slot usually consists of an uplink synchronization code (SYNC_UL) with a length of 128 chips and a guard interval of 32 chips. When the UE is in the air registration and random access state, it will first transmit UpPTS, and when it gets a response from the network , sending a request on RACH (Random Access Channel). For the received UpPTS, the network side uses the possible uplink synchronization code (SYNC_UL) to detect the matched filtering method in the specified search window, estimates the delay, and sends a response notification on the FPACH (forward physical access channel) The UE makes a corresponding time adjustment when sending a signal next time, and establishes uplink synchronization with the base station.

Uplink synchronization maintenance is implemented by using the middle pilot field of each uplink regular time slot in the subframe structure. The above seven regular time slots are divided into time slots in different directions of uplink and downlink, each time slot has 864 chips, and consists of two 352-chip data fields and one 144-chip training sequence (middle pilot) field and a 16-chip slot-protected space (GP).

The 3GPP ( ^3rd Generation Partnership Project 3rd Generation Mobile Communication Partner Project) protocol 25.224 v480 describes the synchronization maintenance as follows: Uplink synchronization is maintained by sending the uplink advance time relative to the downlink reception time. The maintenance of uplink synchronization can use the middle pilot area of 864 chips in each uplink time slot. Each uplink time slot can carry multiple UEs. The middle pilots of each UE are different in each uplink time slot. Node B can estimate the time by calculating the channel impulse response of each UE in the same time slot, and then, in the next available downlink time slot, Node B sends a synchronization shift (Synchronization Shift, SS) command to enable UE to adjust appropriately its launch time.

The 3GPP protocol 25.221 v470 describes the sending of the SS as follows: for each user, the uplink synchronization control command (Up link Sync Command, ULSC) information should be sent at least once in each subframe. For each allocated slot, it is signaled independently whether the slot carries ULSC or not. If a slot carries ULSC, then SS symbols are sent in the data portion of the traffic burst, and they are transmitted using the physical channel with the lowest physical channel sequence number (p) in that slot. SS symbols can also be sent on multiple physical channels in one slot. For this purpose, the upper layer protocol allocates another N _SS physical channels for each time slot respectively. The SS symbols are transmitted using the N _SS + 1 physical channels with the smallest physical channel sequence numbers in the time slot. If the result given by the rate matching is N _RM < N _SS +1 of the remaining physical channels in the time slot, then the SS symbols are only transmitted using the remaining N _RM physical channels. The SS is used to command the timing adjustment (k/8) Tc every M subframes, where Tc is the chip interval. k and M are notified by network signaling. SS transmits once every 5ms subframe.

M (value range 1-8) and k (value range 1-8) can be adjusted during the established call process, and can also be re-adjusted during the call process. Each downlink SS symbol corresponds to an uplink time slot, which depends on the allocated uplink time slot and the downlink allocated SS symbol. For each uplink time slot, the synchronous switching command must follow the following rules, that is, SS mapping (the following equation is used to determine the uplink time slot controlled by the corresponding SS symbol):

UL _pos =(SFN′·N _SSsymbols +SS _pos +((SFN′·N _SSsymbols +SS _pos )div(N _ULslot )))mod(N _ULslot )

Here, UL _pos is the sequence number of the controlled uplink time slot; SFN' is the system frame number of the recorded subframe, and the system frame number (SFN) of the wireless frame can be obtained from SFN', through SFN=SFN'/2, where is an integer divisible operation; N _SSsymbols is the number of SS symbols in a frame; SS _pos is the symbol number of the corresponding SS in a subframe; N _ULslot is the number of uplink slots in a subframe.

The above agreement stipulates the method of estimating ULSC through channel impulse response for uplink synchronization, and stipulates which downlink SS symbol the ULSC of each uplink time slot should be mapped to, that is, the mapping formula is given. It needs to be modified once, and the TD-SCDMA system supports multiple uplink and downlink time slots for one UE, but it does not specify how to send the uplink ULSC to the downlink SS symbol. Therefore, how to write the ULSC into the downlink time slot according to the mapping formula of the protocol, especially to send the SS symbol immediately in the next available downlink time slot, instead of delaying several subframes; The least information is transmitted to reduce system computing and communication burden; how to ensure that the SS symbol is modified every M times instead of every time has become a difficult problem in the current prior art.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for mapping terminal synchronization control commands in a multi-slot communication system, which realizes the downlink mapping of user terminal maintenance and uplink synchronization control commands in the base station uplink synchronization function specified in the 3GPP protocol , so that the synchronization offset symbol can be sent to the user terminal immediately in the next available downlink time slot, so that the uplink synchronization between the user terminal and the base station can be quickly established, and the data interaction between the uplink and downlink time slots is very important for the internal operation and operation of the base station The burden of communication is small.

In order to solve the above technical problems, the present invention provides a method for mapping terminal synchronization control commands in a multi-slot communication system. The method takes one subframe as the processing cycle and includes the following steps:

(a) The base station controller judges whether the user terminal needs to modify the synchronization offset command in the current subframe. If the synchronization offset command needs to be modified, step (b) is performed; otherwise, the synchronization offset symbol mapping is not performed in this subframe, and the synchronization offset Fill in the corresponding synchronization offset value in the previous subframe in the symbol;

(b) The base station controller calculates the uplink synchronization control command of the user terminal and the position number of the uplink time slot carrying the uplink synchronization control command in the uplink time slot occupied by the user terminal, that is, the uplink time slot sequence number;

(c) According to the rule of synchronization offset symbol mapping, the base station controller reversely calculates and obtains the synchronization offset symbol number in one or more downlink time slots corresponding to the uplink time slot sequence number carrying the uplink synchronization control command, said The calculation formula of the synchronization offset symbol mapping rule is

UL _pos =(SFN′·N _SSsymbols +SS _pos +((SFN′·N _SSsymbols +SS _pos )div(N _ULslot )))mod(N _ULslot )

Among them, UL _pos is the uplink time slot number; SFN' is the system frame number of the recorded subframe; NSS _symbols is the total number of synchronization offset symbols in a frame; SS _pos is the symbol number of the corresponding synchronization offset in a subframe ; N _ULslot is the number of uplink time slots of the user terminal in a subframe;

(d) The base station controller calculates the downlink where the synchronization offset symbol corresponding to the uplink synchronization control command is located according to the acquired number of synchronization offset symbols configured in each downlink time slot occupied by the user terminal A time slot and a synchronization offset symbol position in the downlink time slot;

(e) The base station controller sends the uplink synchronization control command to the synchronization offset symbol position of the downlink time slot obtained in step (d).

Further, the above method may have the following characteristics: the method for judging whether the user terminal needs to modify the synchronization offset command in the step (a) is to judge whether the number of subframes recorded since the user terminal is established is a multiple of M, and M Notified by network signaling, its value ranges from 1 to 8, and can be adjusted or re-adjusted during the established call.

Further, the above method may have the following characteristics: in the step (b), the base station controller calculates the uplink synchronization control command of the user terminal through the channel impulse response, and the uplink time slot number can be obtained through the configuration of the network side.

Further, the above method may have the following characteristics: the value of SFN' in the step (c) is the count value of a counter maintained by the base station network side itself, the counter is incremented by 1 every 5ms, and the value range is 0-8191.

Further, the above method may have the following characteristics: the value of NSS _symbols in the step (c) is obtained by accumulating the number of synchronization offset symbols of each downlink time slot occupied by the user terminal, and the number of synchronization offset symbols of the downlink time slot is Obtained from the user terminal information configured on the network side.

Further, the above method may have the following characteristics: the value of N _Ulslot in the step (c) is configured by the network side when allocating user terminal related resources.

Furthermore, the above-mentioned method may have the following characteristics: there may be one or several user terminals, and when the number of user terminals is greater than 1, the base station controller performs parallel processing on several user terminals.

Compared with the prior art, the method for mapping terminal synchronization control commands in the multi-slot communication system of the present invention has the following advantages:

A. This method is a reverse application of the synchronization offset symbol mapping rule stipulated in the 3GPP protocol, and obtains its corresponding synchronization offset symbol position on the basis of the known uplink time slot number, realizing the maintenance and synchronization of the user terminal specified in the agreement. The uplink synchronization control command in the uplink synchronization function of the base station is mapped to the downlink;

B. In this method, the mapping of the synchronization offset symbol is completed in the uplink time slot, without waiting for the uplink synchronization control command of other uplink time slots, and the uplink synchronization control command is written into the designated downlink time slot every M subframes The position of the synchronization offset symbol once, so that the synchronization offset symbol can be sent to the user terminal immediately in the next available downlink time slot, so as to quickly establish the uplink synchronization between the user terminal and the base station, and the uplink and downlink time slots The burden of data interaction on the internal calculation and communication of the base station is very small.

Description of drawings

1 is a schematic flow chart of a mapping method for terminal synchronization control commands in a multi-slot communication system according to the present invention;

Fig. 2 is an example diagram of the mapping relationship of the corresponding synchronization offset symbol of a downlink time slot using the method to control the uplink time slot;

Fig. 3 is a schematic diagram of mapping the uplink synchronization control command generated by applying the method and sending it to the position of the synchronization offset symbol of the downlink time slot;

Fig. 4 is a diagram of the key nodes required from the uplink synchronization control command to the synchronization offset symbol of the downlink time slot in the present invention.

Detailed ways

In order to deeply understand the method for mapping terminal synchronization control commands in the multi-slot communication system of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1, the mapping method of the terminal synchronization control command in the multi-slot communication system of the present invention uses one subframe as the processing period, and describes it as a single UE (user terminal) in the example. If multiple UEs need to be processed, the base station controller Multiple UEs can be processed in parallel, including the following steps:

Step 1, the base station controller judges whether the UE in the current subframe needs to modify the SS (synchronization offset) command, that is, judges whether the number of subframes recorded since the UE is established is a multiple of M, and M can be notified by network signaling, which takes The value ranges from 1 to 8, which can be adjusted or re-adjusted during the established call process. If the SS command needs to be modified, perform step 2. Otherwise, the SS symbol mapping will not be performed in this subframe, and the previous subframe will be filled in the SS symbol. The corresponding SS value in the frame;

Step 2, the base station controller calculates the ULSC (uplink synchronization control command) of the UE and the position number of the uplink time slot carrying the ULSC in the uplink time slot occupied by the UE, that is, the uplink time slot sequence number UL _pos , In fact, in the process of maintaining the uplink synchronization of the user terminal to the base station, the base station controller estimates the ULSC value through the channel impulse response. The uplink time slot occupied by the UE is configured by the network side, so the current uplink time slot is in the UE The number UL _pos in the occupied uplink time slot can be obtained;

Step 3, according to the rules of SS symbol mapping, the base station controller reversely calculates to obtain the SS symbol number SS _pos in one or more downlink time slots corresponding to the UL _pos obtained in step 2, the calculation formula of the SS symbol mapping rule for

UL _pos ＝(SFN′·N _SSsymbols +SS _pos +((SFN′·N _SSsymbols +SS _pos )div(N _ULslot )))mod(N _Lslot )

Among them, SFN' is the number of system frames for recording subframes, and its value is the count value of a counter maintained by the base station network side. The counter is incremented by 1 every 5ms, and the value range is 0 to 8191; NSS _symbols are The total number of SS symbols, its value is obtained by accumulating the number of SS symbols of each downlink time slot occupied by the UE, and the number of SS symbols of the downlink time slot is obtained from the UE information configured on the network side; N _ULslot is the UE in The number of uplink time slots in a subframe, its value is configured by the network side when allocating UE-related resources;

Figure 2 shows an example diagram of the mapping relationship of the corresponding SS symbol controlling the uplink time slot of a downlink time slot. The three uplink time slots occupied by the UE in the figure describe the number of SS symbol configurations in two cases, and the left side is the case 1. Configure 2 SS symbols; configure 4 SS symbols for case 2 on the right, that is, N _ULslot = 3, N _SSsymbols = 2 or N _SSsymbols = 4, and 1 ^st UL _pos in the figure refers to the first one calculated in the mapping formula UL _pos , the corresponding other UL _pos are shown by the arrows in the figure;

Step 4, the base station controller respectively obtains the number of SS symbols configured in each downlink time slot occupied by the UE through the UE information configured by the network side;

Step five, the base station controller calculates the downlink time slot where the SS symbol corresponding to the ULSC is located and the position of the SS symbol in the downlink time slot according to the result obtained in step four;

In step six, the base station controller writes or sends the ULSC to the SS symbol position of the downlink time slot obtained in step five.

Figure 3 shows the mapping situation of the ULSC command generated by the application of this method and sent to the SS symbol position of the downlink time slot. It is assumed that the number of uplink time slots N _ULslot = 3 occupied by the UE is respectively time slot 1, Time slot 2 and time slot 3; the UE occupies two downlink time slots, namely time slot 4 and time slot 5; and a SS symbol of the UE is configured in time slot 4, and a SS symbol of the UE is configured in time slot 5 SS symbol.

In this case, the SS symbols can be generally numbered as 0, 1, 2, and 3, where the SS symbols of time slot 4 are numbered 0, and the SS symbols of time slot 5 are numbered 1-3. In Figure 3, the ULSC generated in uplink time slot 1 is put into the SS symbol of downlink time slot 4, that is, the SS symbol whose total number is 0 is occupied; the ULSC generated in uplink time slot 2 needs to be put into two SS symbols according to the mapping relationship , respectively corresponding to the SS symbols with the total number 1 and 3, that is to say, corresponding to the positions of the SS symbols with the numbers 0 and 2 in the time slot 5; the ULSC generated in the uplink time slot 3 is put into the second SS with the total number according to the mapping formula The symbol position, that is, the SS position numbered 1 in slot 5.

This insertion process after obtaining the SS location information required by the ULSC is optimal, and the specific function of mapping is realized by using the minimum information. This method not only avoids the need for the ULSC communication process generated by all uplink time slots when the uplink time slot is mapped (this will cause the mapping to be done only in the last uplink time slot, it is easy to cause delays in waiting for information in other time slots and make It cannot be sent out immediately in the adjacent downlink time slot), and it also avoids the completion of mapping in the downlink time slot (this will require that the mapping be completed in the first downlink time slot, requiring all ULSCs to be sent to this time slot, And the SS generated in this time slot needs to be sent to other downlink time slots, and it is easy to cause delay in waiting for other time slot information in the process so that it cannot be sent out immediately in the adjacent downlink time slot).

In the present invention, the key nodes required from the ULSC command to the SS symbol of the downlink time slot are shown in Figure 4. From the ULSC to the SS symbol, after knowing the uplink time slot number and the SS number, the corresponding DLTS number can be obtained and in this SS number inside DLTS and sent directly to bit.

The invention discloses a synchronization control command mapping method for uplink synchronization between a terminal and a base station in a multi-slot communication system. This method is simple and efficient. First, obtain the current uplink time slot number and its UE and mapping-related information. In this uplink time slot, the SS mapping is completed in advance, and the location required for ULSC transmission is obtained, and then the transmission is completed directly in one step, reducing the amount of calculation. and storage space, avoiding the impact of communication delay on the effectiveness of synchronization control commands, and ensuring rapid establishment of synchronization maintenance.

The above specific embodiments are only used to illustrate the present invention, rather than to limit the present invention. Although the current embodiment can be used in the TD-SCDMA system, the method is not limited to the TD-SCDMA system, as long as there are multiple uplink and downlink Gap communication systems may be used with beneficial effects.

Claims (8)

1. The mapping method of terminal synchronous control command is characterized in that in l, a kind of multiple time slot communication system, and this method is the processing cycle with a subframe, comprises the steps:

   (a) base station controller judges whether user terminal needs to revise simultaneous bias order in the current subframe, if need to revise simultaneous bias order, execution in step (b) then, otherwise this subframe is not carried out the simultaneous bias sign map, inserts corresponding synchronous deviant in the subframe in the simultaneous bias symbol;

   (b) the base station controller Position Number of ascending time slot in the shared ascending time slot of described user terminal that calculate the uplink synchronous control command of described user terminal and carry this uplink synchronous control command, i.e. ascending time slot sequence number;

   (c) according to the rule of simultaneous bias sign map, the reverse simultaneous bias symbol number that calculates in the pairing one or more descending time slots of the ascending time slot sequence number of carrying described uplink synchronous control command of base station controller, the computing formula of described simultaneous bias sign map rule is

   UL _pos＝(SFN′·N _SSsymbols+SS _pos+((SFN′·N _SSsymbols+SS _pos)div(N _ULslot)))mod(N _ULslot)

   Wherein, UL _PosBe the ascending time slot sequence number; SFN ' is the system frame number of record subframe; Nss _SymbolsIt is simultaneous bias symbolic number total in the frame; SS _PosIt is the symbol number of respective synchronization skew in a subframe; N _ULslotBe the ascending time slot number of described user terminal in a subframe;

   (d) base station controller calculates the descending time slot at the pairing simultaneous bias symbol of described uplink synchronous control command place and the simultaneous bias character position in this descending time slot according to the simultaneous bias symbol numbers that the described user terminal that obtains disposes in its each shared descending time slot;

   (e) base station controller is sent to described uplink synchronous control command the simultaneous bias character position of the descending time slot that step (d) draws.
2. 2, the mapping method of terminal synchronous control command in the multiple time slot communication system according to claim 1, it is characterized in that: judge that the method whether user terminal needs to revise simultaneous bias order is in the described step (a), whether the number of sub frames that judgement is write down after user's terminal is set up is the multiple of M, M is notified by network signal, and the span of M is 1～8.
3. 3, the mapping method of terminal synchronous control command in the multiple time slot communication system according to claim 2 is characterized in that: described M can adjust or readjust in calling procedure setting up in the calling procedure.
4. 4, the mapping method of terminal synchronous control command in the multiple time slot communication system according to claim 1, it is characterized in that: base station controller calculates the uplink synchronous control command of described user terminal by channel impulse response in the described step (b), and the ascending time slot sequence number can be obtained by the configuration of network side.
5. 5, the mapping method of terminal synchronous control command in the multiple time slot communication system according to claim 4, it is characterized in that: the value of SFN ' is the count value of a counter safeguarding voluntarily of base station network side in the described step (c), this counter adds 1 every 5ms, and span is 0～8191.
6. 6, the mapping method of terminal synchronous control command in the multiple time slot communication system according to claim 5 is characterized in that: Nss in the described step (c) _SymbolsThe simultaneous bias symbolic number of each descending time slot of taking by the described user terminal that adds up of value obtain, the simultaneous bias symbolic number of descending time slot is obtained from the user terminal information of network side configuration.
7. 7, the mapping method of terminal synchronous control command in the multiple time slot communication system according to claim 6 is characterized in that: N in the described step (c) _UlslotValue dispose when the distributing user terminal related resource by network side.
8. 8, the mapping method of terminal synchronous control command in the multiple time slot communication system according to claim 1, it is characterized in that: described user terminal can be one or several, when the number of user terminal greater than 1 the time, base station controller is taked parallel processing to several user terminals.

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