Method and system for updating system frame number

System frame number update method and system technical field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a system frame number (System Frame Number,

SFN) update method and system.

Background technique

[0002] In order to meet the increasing demand for high-bandwidth and high-speed mobile access, the Third Generation Partnership Projects (3GPP) has launched the Long-Term Evoluti on Advance (LTE-Advanced) standard . LTE-Advanced retains the core of LTE for the evolution of Long-Term Evolution (LTE), and uses a series of technologies to expand the frequency domain and space domain on this basis, in order to improve spectrum utilization and increase system capacity And other purposes.

[0003] The wireless relay (Wireless Relay) technology is one of the technologies in LTE-Advanced, which aims to expand the coverage of cells, reduce blind spots in communication, balance load, transfer services in hotspots, and save user terminals. Equipment, UE) transmit power. Figure 1 is a schematic diagram of a network structure using wireless relay technology. As shown in Figure 1, some relay nodes (RN) are added between the original base station DeNB and UE, and these newly added RNs and DeNBs are connected wirelessly. , There is no wired connection with the transmission network. The downlink data arrives at the DeNB first, then is transmitted to the RN, and then the RN is transmitted to the UE, and vice versa for the uplink. This method shortens the distance between the antenna and the UE, and can improve the link quality of the UE, thereby increasing the system's spectrum efficiency and user data rate.

[0004] The UE obtains the network side information through the system broadcast information, and the system broadcast information is also an important means for the network side to configure the UE. In the LTE system, the system broadcast information is divided into three parts: Master Information Block (Master Information Block, MIB), System Information Block 1 and other system information blocks. The MIB also includes downlink system bandwidth and physical hybrid automatic request retransmission instructions. Channel configuration information and SFN three parts.

[0005] The method for the UE to learn SFN is to read the MIBo MIB in the system message with a period of 40 ms, and the first transmission on subframe #0 of the radio frame with SFN mod 4 =0, and all other radio frames in a period Retransmit in subframe #0. SFN has 10 bits in total, MIB explicitly defines its 8 high-significant bits, and the remaining 2 low-significant bits are obtained from the decoding of the physical broadcast channel (Physical Broadcast CHannel, PBCH). In other words, when the UE and the eNB are synchronized, the UE knows the frame number, cycle duration, and boundary of the radio frame. In this 40ms PBCH transmission time interval, 1~4 radio frames are respectively counted as 00 and 01 , 10 and 11. Therefore, the 8 most significant bits of SFN are obtained explicitly from the MIB content, and the 2 least significant bits are obtained from the transmission position of the wireless frame.

[0006] In a network configured with an RN, the RN provides functions and services similar to those of a common eNB for UEs accessing its cell, and the radio interface between the two is called an access link (Access Link), also known as Uu interface. The RN accesses an eNB that serves it through a wireless interface in a manner similar to that of a normal UE. The eNB that serves the RN is called Donor eNB, or DeNB for short. The wireless interface between RN and DeNB is called Backhaul Link (Backhaul Link). ), also known as Un port.

[0007] According to whether the center frequencies used by the RN at the Un port and the Uu port are the same, the RN can be divided into two working modes: "Inband" and "Outband". Inband Relay refers to the RN using the same frequency at the Un port and Uu port, and Outband Relay refers to the RN using different frequencies at the Un port and Uu port. For Inband Relay, the DeNB-Relay link and Relay-UE link use the same uplink and downlink frequencies, which means that Relay cannot be connected in Un.

While receiving (or sending) wireless signals through the Uu port, simultaneously sending (or receiving) wireless signals through the Uu port. Unless Relay can isolate the transceiver wireless signal through a specific antenna technology, the wireless signal transceiver of the Un and Uu interface will interfere with each other. [0008] The solution to the problem of Inband Relay self-interference is that the RN adopts a fake MB SFN (Multimedia Broadcast Single Frequency Network) subframe solution at the Un port and the Uu port. This solution refers to defining some subframes at the Un port as Un downlink subframes, and the Uu port downlink subframes corresponding to these Un downlink subframes are set as MBSFN subframes at the Uu port. Since the UE receives control signals in the first 2 symbols in the MBSFN subframe, and does not receive unicast data in the remaining symbols, the RN can stop sending downlink signals during this period and switch to the corresponding The Un downlink subframe receives the downlink data of the Un port, thereby realizing the downlink time division work and avoiding the interference between the uplink and the downlink at the same frequency. Therefore, the Un interface downlink subframe must correspond to the MBSFN subframe. In the standard, subframes with subframe numbers 0, 4, 5, and 9 need to transmit MIB, system information block 1, and paging messages, and the UE needs to receive all data in these subframes. Therefore, these subframes cannot be configured as MBSFN subframes. Accordingly, these subframes cannot be configured as Un downlink subframes at the Un interface.

[0009] It can be seen that for Inband Relay, when the system frame number of the DeNB hops, the RN cannot obtain the change of the system frame number by reading the system information broadcast. If the RN cannot update its own system frame number, then when the RN needs to restart and initiates random access as an ordinary UE, it cannot read the SFN-identified system message broadcast by the eNB, that is, it cannot obtain random access. Failure to access the required resources. Therefore, for Inband Relay, the DeNB needs to transfer updated system information to the RN through other applicable signaling. In addition, since the SFN is continuously increasing over time, and the delay between the DeNB sending the signaling and the RN receiving the signaling is indeterminate, it is difficult to ensure that when the RN receives the signaling, the SFN in it The value is consistent with the real DeNB cell SFN. Therefore, a method is needed to enable the RN to obtain the SFN of the DeNB cell reliably and accurately.

Summary of the invention

[00101 In view of this, the main purpose of the present invention is to provide a system frame number update method and system. When the system frame number of the DeNB jumps, the DeNB can accurately instruct the RN to update the system frame number, thereby ensuring the system stability.

[0011] In order to achieve the above objective, the technical solution of the present invention is achieved as follows:

[0012] A system frame number SFN update method, including:

[0013] When the system frame number of the DeNB hops, the DeNB sends the deviation value before and after the SFN hopping or the SFN value after the hopping to the relay node RN through the dedicated radio resource control RRC signaling, which is used for the SFN of the RN Update.

[0014] In the case where the DeNB sends the deviation value before and after the SFN hopping to the RN through RRC dedicated signaling, the RRC dedicated signaling also carries a flag bit indicating the positive or negative of the deviation value.

[0015] In the case that the DeNB sends the hopping SFN value to the RN through RRC dedicated signaling, the RRC dedicated signaling also carries a flag bit that indicates the effective bit of the transmitted SFN.

[0016] The method further includes: after receiving the RRC dedicated signaling, the RN uses the sum of the current SFN value and the deviation value carried in the RRC dedicated signaling as the updated SFN value.

[0017] The method further includes: after the RN receives the RRC dedicated signaling, updating the SFN value to the SFN value carried in the RRC dedicated signaling.

[0018] An SFN update system, including: DeNB and RN; wherein,

[0019] The DeNB is used to send an SFN to the RN through RRC dedicated signaling when the system frame number changes

The deviation value before and after the jump or the SFN value after the jump.

[0020] In the case that the DeNB sends the deviation value before and after the SFN hopping to the RN through RRC dedicated signaling, the RRC dedicated signaling also carries a flag bit indicating the positive or negative of the deviation value.

[0021] In the case that the DeNB sends the hopping SFN value to the RN through RRC dedicated signaling, the RRC dedicated signaling also carries a flag bit that indicates the effective bit of the transmitted SFN.

[0022] The RN is also configured to, after receiving the RRC dedicated signaling from the DeNB, use the sum of the current SFN value and the deviation value carried in the RRC dedicated signaling as the updated SFN value.

[0023] The RN is further configured to update the SFN value to the SFN value carried in the RRC dedicated signaling after receiving the RRC dedicated signaling from the DeNB.

[0024] The system frame number update method and system of the present invention, when the system frame number of the DeNB hops, the DeNB sends the deviation value before and after the SFN hopping to the RN through radio resource control (Radio Resource Control, RRC) dedicated signaling Or the SFN value after the jump is used for the SFN update of the RN, so that the RN can accurately and reliably implement the SFN update and ensure system stability.

Description of the drawings

[0025] FIG. 1 is a schematic diagram of a network structure using wireless relay technology;

[0026] FIG. 2 is a schematic flowchart of a method for updating a system frame number according to Embodiment 1 of the present invention;

[0027] FIG. 3 is a schematic flowchart of a method for updating a system frame number according to Embodiment 2 of the present invention;

[0028] FIG. 4 is a schematic flowchart of a method for updating a system frame number in Embodiment 3 of the present invention;

[0029] FIG. 5 is a schematic flow chart of a method for updating a system frame number in Embodiment 4 of the present invention; [0030] FIG. 6 is a schematic flow chart of a method for updating a system frame number according to Embodiment 5 of the present invention.

Detailed ways

[0031] The basic idea of the present invention is that when the system frame number of the DeNB hops, the DeNB sends the deviation value before and after the SFN hopping or the SFN value after the hopping to the RN through RRC dedicated signaling, which is used for the RN's SFN update.

[0032] It should be noted that when the RN is powered on or recovers after a radio link failure (RLF), the RN receives the MIB as the UE to obtain the SFN. At this time, the complete SFN is known, and the RN Synchronized with DeNB. When the RN works as an RN, if the SFN value changes, the DeNB of the macro cell will notify RNo of the SFN change through RRC signaling.

[0033] Specifically, there are two implementation manners for notifying the RN of the SFN hopping status through the RRC dedicated signaling: [0034] 1) The RRC dedicated signaling carries the deviation value before and after the SFN hopping.

[0035] After the SFN on the DeNB side hops, the difference from the original SFN value is transmitted to the RN through RRC dedicated signaling. This value can be positive or negative depending on the specific situation. At this time, the RRC dedicated signaling It also needs to carry a flag indicating the positive or negative of the deviation value. The RN receives the RRC dedicated signaling indicating the SFN update in a certain radio frame, and displays the update result in the next radio frame. This method is more flexible and reliable.

[0036] Correspondingly, after receiving the RRC dedicated signaling, the RN uses the sum of the current SFN value and the deviation value carried in the RRC dedicated signaling as the updated SFN value.

[0037] 2) The RRC dedicated signaling carries the SFN value (ie, the absolute value) after the hopping.

[0038] After the SFN on the DeNB side hops, according to the specific hopping situation, the DeNB can transmit the 8 high-significant bits of the SFN

Or the 10 valid bits of the complete SFN are given to the RN. At this time, the RRC dedicated signaling also needs to carry a flag bit indicating the valid bits of the SFN to be transmitted. RN receives RRC dedicated signaling indicating SFN update in a certain radio frame, and displays the update result in the next radio frame.

[0039] Correspondingly, after receiving the RRC dedicated signaling, the RN updates the SFN value to the SFN value carried in the RRC dedicated signaling.

[0040] It should be noted that if the SFN of the DeNB cell does not hop, and the information unit indicating the SFN is set as a mandatory option in the RRC signaling, then the DeNB indicates other system information (System Information, SI) When updating, set the item indicating SFN in the signaling to an invalid value.

[0041] The present invention also provides a system frame number update system, the system includes: DeNB and RN; wherein,

[0042] The DeNB is used to send the deviation value before and after the SFN hopping or the SFN value after the hopping to the RN through RRC dedicated signaling when the system frame number hops.

[0043] In the case that the DeNB sends the deviation value before and after the SFN hopping to the RN through RRC dedicated signaling, the RRC dedicated signaling also carries a flag bit indicating the positive or negative of the deviation value.

[0044] Correspondingly, the RN is also used to, after receiving the RRC dedicated signaling from the DeNB, compare the current SFN value with

The sum of the deviation values carried in the RRC dedicated signaling is used as the updated SFN value.

[0045] In the case where the DeNB sends the hopping SFN value to the RN through RRC dedicated signaling, the RRC dedicated signaling also carries a flag bit that indicates the effective bit of the transmitted SFN.

[0046] Correspondingly, the RN is also used to update the SFN value to the SFN value carried in the RRC dedicated signaling after receiving the RRC dedicated signaling from the DeNB.

[0047] The present invention will be described in detail below with reference to the drawings and specific embodiments.

Example 1

[0049] When the DeNB and the RN are synchronized, the SFN correspondences of the two are the same. When the SFN on the DeNB side hops, it will send the changed deviation value and flag bit to the RN through RRC dedicated signaling. When the RN receives the signaling in a certain radio frame, it will reply to the DeNB to confirm and update the SFN = The original SFN + deviation value, and the result of the change will be displayed in the next wireless frame (in the embodiment, the SFN is described as a decimal value).

[0050] The flag bit Flag is an optional cell with a length of 2 bits included in the RRC dedicated signaling. Flag = 00 represents the positive deviation of the SFN hopping; Flag = 01 represents the SFN hopping Negative deviation value; Flag = 10 means that the 8 high-bit absolute values of SFN are sent; Flag = 11 means that the absolute value of 10 bits of SFN is complete.

[0051] FIG. 2 is a schematic flowchart of a method for updating a system frame number in Embodiment 1 of the present invention. As shown in FIG. 2, the method includes: [0052] Step 201: DeNB and RN are always synchronized, when the SFN of the two radio frames is 549 When the SFN of the next radio frame should be incremented to 550 according to the time sequence, the SFN hop on the DeNB side becomes 1000.

[0053] Step 202: The SFN on the DeNB side undergoes a jump, and it sets the relative deviation before and after the jump Value=1000-550=450, and the flag bit Flag=00 (as mentioned above, it indicates that the SFN is positive. Relative value) is transmitted to RN through RRC SI Update signaling.

[0054] Step 203: The RN returns an ACK to the DeNB after successfully receiving the RRC signaling.

[0055] When the DeNB receives the ACK, it knows that the RN side signaling is successfully received, and before the RRC signaling is received (including the radio frame that received the signaling), the RN still counts according to the time sequence based on the original SFN value (such as SFN)._ffl =549~SFN_en = 550). If the DeNB does not receive the acknowledgment from the RN, it will retransmit the RRC signaling carrying the offset value and the flag bit. In addition,

After receiving the RRC signaling, the RN performs the update according to the signaling instructions, and does not have to do it after replying to the DeNB with a confirmation message.

[0056] Step 204: Assume that the RN is in the SFN_en The radio frame of = 550 receives this RRC signaling, and learns that the SFN hopping of the DeNB has increased by 450. The SFN of the RN in the next radio frame should increase to 551 according to the time sequence (at this time, the SFN_DeNBThe updated value is incremented to 1001 according to the time sequence), but according to the received deviation value and the flag bit, it is updated to SFN = 551+450 = 1001, and it is resynchronized with the DeNB.

Example 2

[0058] This embodiment is similar to Embodiment 1, except that the change amount in this example is a negative value, and the corresponding flag bit is changed. FIG. 3 is a schematic flowchart of a method for updating a system frame number in Embodiment 2 of the present invention. As shown in FIG. 3, the method includes: [0059] Step 301: DeNB and RN are always synchronized. When the SFN of the two radio frames is 549, the following The SFN of a radio frame should increase to 550 according to the time sequence, but the SFN hop on the DeNB side becomes 300.

[0060] Step 302: The SFN on the DeNB side has a jump, then it sets the relative deviation before and after the jump Value = 300-550 = -250, and the flag bit Flag = 01 (indicating that the SFN negative relative value is sent) Transmitted to RNo through RRC SI Update signaling

[0061] Step 303: After the RN successfully receives the RRC signaling, it replies ACK to the DeNB. The DeNB knows that the RN-side signaling is successfully received after receiving the ACK, and before receiving the RRC signaling (including the one that receives the signaling) Radio frame), RN still counts according to the time sequence based on the original SFN value (such as SFN_en =549~SFN_en = 550), if the DeNB does not receive the confirmation from the RN, it will retransmit the RRC signaling carrying the offset value and the flag bit. In addition, the RN performs the update according to the signaling instructions after receiving the RRC signaling, and does not need to perform the update after replying to the DeNB with a confirmation message.

[0062] Step 304: Assume that the RN is in the SFN_en The radio frame of = 550 receives this RRC signaling, and learns that the SFN hopping of the DeNB is reduced by 250. The SFN of the RN in the next radio frame should change to 551 according to the time sequence (at this time, the SFN_DeNBThe updated value is incremented to 301 according to the time sequence), but according to the received deviation value and flag bit, it is updated to SFN = 551 + (-250) = 301, and it is resynchronized with the DeNB.

Embodiment 3

[0064] This embodiment transmits the absolute value of the SFN. As mentioned earlier, the 2 low-significant bits of the SFN of each radio frame can be obtained by sequentially increasing the radio frame bits according to the time sequence. If the 8 high-order bits of the SFN on the DeNB side jump at a certain time, based on the HARQ mechanism and its Timing HARQ RTT Time = 8ms, DeNB has the ability to know the time when transmission signaling arrives at RN (the DeNB side knows the number of retransmissions), it sends RRC dedicated signaling to indicate that RN should update when receiving the signaling Value.

[0065] After receiving the RRC dedicated signaling in a certain radio frame, the RN replies to the DeNB for confirmation, and will display the updated result in the next radio frame, where the SFN_fflThe 8 high bits of the SFN are updated according to the received value, and the 2 low bits are still incremented by 1 according to the timing count, and the complete SFN is resynchronized with the DeNB.

[0066] If the DeNB does not receive the confirmation from the RN, it will retransmit the RRC dedicated signaling indicating the correct update value of the SFN. In addition, the RN performs the update according to the signaling instructions after receiving the RRC dedicated signaling, and does not need to perform the update after replying to the DeNB with a confirmation message.

[0067] FIG. 4 is a schematic flowchart of a method for updating a system frame number in Embodiment 3 of the present invention. As shown in FIG. 4, the method includes: [0068] Step 401: DeNB and RN are directly synchronized, but in SFN = 0000 1111 00 wireless After the frame, SF\_DeNB The 8 high-significant bits jump to 1111 0000, and the 2 low-significant bits increase to 01 according to the sequence, then SFN_DeNB= 1111 000001. [0069] Step 402: The DeNB sends an RRC SI Update message to the RN, where the SFN information element value is the new SFN high of 8.

The bit value is 11110000. It also includes the flag bit Flag = 10, which means that the transmitted SFN value is the absolute value of the upper 8 bits.

[0070] It should be noted that if the DeNB is in the SFN_DeNBAfter the hopping occurs, there is currently no applicable channel resource to send this RRC dedicated signaling, and it can only be sent when there are available resources. And as mentioned above, based on HARQ timing and DeNB capabilities, it can know in which radio frame the RN can receive this signaling. If the SFN on the DeNB side has been increased from the updated 1111000001 to 1111000100 when the RN successfully receives it, that is, the 8 high bits have been carried after the update, then the RRC dedicated signaling sent by the DeNB to the RN should indicate the SFN₈ = 11110001ο

[0071] In other words, when the RRC dedicated signaling sent by the DeNB to the RN carries the absolute value of the SFN, this absolute value should be the value that the RN should update at the moment the signaling is received, not the DeNB Which SFNo has been updated [0072] Step 403: After successfully receiving the RRC signaling, the RN replies an ACK to the DeNB.

[0073] Before receiving the RRC signaling (including the radio frame in which the signaling is received), the RN still counts according to the time sequence based on the original SFN value (such as SFN_en = 0000111100 ~SFN^m 0000111110), the DeNB knows that the RN side signaling is successfully received after receiving the ACK.

[0074] Step 404: RN receives RRC dedicated signaling when SFNm = 0000111110, and learns that DeNB indicates that it should update the high value of SFN at this moment.₈ = 11110000, then RN updates its 8 high bits according to the instructions, and the low 2 bits are still counted as 11 according to the timing, so the SFN of the next radio frame is SFN_ffl = 1111110011, i.e. resynchronize with DeNB To

Example 4

[0076] After the DeNB and the RN are synchronized, the SFN correspondences of the two are the same. If the SFN on the DeNB side hops at a certain moment (both high and low bits hop), as mentioned above, based on the DeNB knows the time when the transmission signaling arrives at the RN, it is indicated in the RRC dedicated signaling sent The value that the RN should update after receiving the signaling also includes a flag bit, which indicates that the complete 10bits absolute value of the SFN is sent in the signaling.

[0077] After receiving the RRC dedicated signaling in a certain radio frame, the RN replies to the confirmation to the DeNB, and performs the update according to the value indicated in the signaling. The result will be displayed in the next radio frame, and the DeNB is resynchronized.

[0078] FIG. 5 is a schematic flow chart of a method for updating a system frame number in Embodiment 4 of the present invention. As shown in FIG. 5, the method includes: [0079] Step 501: DeNB is directly synchronized with RN, but in a radio frame with SFN = 0000111100 After SFN_DeNBThe jump becomes 1111000011, that is, both the high and low bits have jumped. At this time, the SFN on the RN side normally increases to 000011110L according to the time sequence. [0080] Step 502: The DeNB sends an RRC SI Update message to the RN, where the SFN cell value is received by the RN. The SFN value that should be updated after this signaling. Based on HARQ timing and DeNB capabilities, it learns that the RN side will be in the SFN_en = 0000111110 when this signaling is received (at this time the SFN on the DeNB side has increased from the updated value to 1111000100 in time sequence), and the updated result will be displayed in the next frame, so the DeNB indicates SFN= 111100010L in the RRC signaling The signaling also includes Flag = 11, which means that the transmitted SFN is a complete 10bits absolute value.

[0081] Step 503: The RN returns an ACK to the DeNB after successfully receiving the RRC signaling.

[0082] Before receiving the RRC signaling (including the radio frame that received the signaling), the RN still counts according to the time sequence based on the original SFN value (such as SFN_en = 0000111100~SFNrn = 0000111110), when the DeNB receives the ACK, it knows that the RN side signaling is successfully received this time.

[0083] If the DeNB does not receive the reply from the RN, it will retransmit the RRC signaling using the HARQ mechanism. At this time, the value indicated in the signaling should be the update result displayed in the next radio frame after the RN receives the RRC dedicated signaling, and the signaling also includes the flag bit Flag=11. In addition, the RN performs the update according to the signaling instructions after receiving the RRC dedicated signaling, and does not have to do it after replying to the DeNB with a confirmation message.

[0084] Step 504: RN is in SFN_en = 0000111110 when the RRC dedicated signaling is received. The signaling includes the complete 10 bits of SFN and the Flag. It is learned that the DeNB indicates that it should be updated to 1111000101 in the next frame, and the RN follows the instructions in the next radio frame. SFN_en = 1111000101, resynchronized with DeNB.

Embodiment 5

[0086] If SFN_DeNBThere is no hopping, but at a certain moment the DeNB needs to send RRC dedicated signaling to the RN to indicate other SI information updates. If the information element indicating the SFN update is configured as an option, it can be omitted at this time; but if If this information unit is configured as a mandatory option, it can be set to an invalid value, such as 0, and does not need to include the flag bit Flag.

[0087] FIG. 6 is a schematic flowchart of a method for updating a system frame number according to Embodiment 5 of the present invention. As shown in FIG. 6, the method includes: [0088] Step 601: DeNB and RN are always strictly synchronized, if the SFN of the radio frame When the increment reaches 550, the DeNB side needs to send RRC signaling to the RN to indicate the SI update, but at this time, the SFN_DeNBThere is no jump. If the information element indicating the SFN update is configured as a mandatory option in the RRC signaling, the DeNB indicates Value = Oo in the RRC dedicated signaling sent to the RN when SFN = 550

[0089] Step 602: When the RN receives this RRC signaling, it learns that the SFN on the DeNB side has not hopped but is still incremented according to the timing. If the reception is successful, it will reply to the DeNB with an ACK, and the DeNB will know that the RN has successfully received the RRC after receiving the ACK Signaling.

[0090] The above are only preferred embodiments of the present invention, and are not used to limit the protection scope of the present invention.