TWI814000B - Method and apparatus for managing handovers in wireless communication system - Google Patents

Abstract

A method for controlling and managing handovers between base stations in adjoining cells in wireless communications enables a user equipment (UE) to report a bit error rate (BER) to a base station having current conduct of communication with the UE. If the BER is greater than a predetermined value, the base station having conduct further determines whether the UE satisfies a handover condition over a period of time and hands conduct over to another base station if the UE satisfies the handover condition for the period of time and if the other base station is not already operating at capacity. An apparatus for controlling and managing handovers is also disclosed.

Description

Method and device for managing handover in wireless communication system

The present invention relates to the technical field of wireless communications, and in particular, to a method and device for managing handover.

In the fourth generation (4G) wireless communication system, the evolved Node B (eNB) uses Adaptive Modulation and Coding (AMC) technology to determine the suitable modulation and available resource blocks for the user equipment. Amount to communicate with this user device. If the 4G signal quality is still poor after using AMC technology, it will switch to the 3G network or handover to another base station (eNB). Although this method has been extended to fifth-generation wireless communications, it also causes other problems.

The arrival of the Internet of Things era will lead to a shortage of 4G resource blocks. If the system triggers the user equipment to change hands from the next-generation base station (gNB) to the eNB based solely on the received power level, the fifth-generation resource block will still be sufficient. Changing hands will lead to a decrease in overall network performance, so this method is not suitable for fifth-generation wireless communications.

In view of this, an object of the present invention is to provide a method and device for managing handover in a wireless communication system, which can manage handover in a 4G/5G wireless network.

The present invention provides a method for managing handover in a wireless communication system. The method includes the following steps: a serving base station receives a measurement report from a user equipment, wherein the measurement report includes: Channel quality index and bit error rate; the serving base station determines whether the bit error rate is greater than a preset bit error rate threshold; when it is determined that the bit error rate is greater than the preset bit error rate threshold, The serving base station determines whether the user equipment satisfies the handover condition; when it is determined that the user equipment satisfies the handover condition, the serving base station determines whether the user equipment continues to satisfy the handover condition within a preset time period. When it is determined that the user equipment continues to meet the handover condition within the preset time period, the serving base station determines whether the current load of the target base station is overloaded; and when it is determined that the current load of the target base station is not When overloaded, the serving base station hands over the user equipment to the target base station.

The present invention also provides a device for managing handover in a wireless communication system, wherein the device includes: a processor; and a memory for storing at least one computer program, wherein the computer program includes: executed by the processor The instruction causes the processor to perform the following steps: the serving base station receives a measurement report from the user equipment, where the measurement report includes a channel quality indicator and a bit error rate; the serving base station determines the bit error Whether the rate is greater than the preset bit error rate threshold; when it is determined that the bit error rate is greater than the preset bit error rate threshold, the serving base station determines whether the user equipment meets the handover condition; when it is determined that the When the user equipment meets the handover condition, the serving base station determines whether the user equipment continues to meet the handover condition within the preset time period; when it is determined that the user equipment continues to meet the handover condition within the preset time period. When the handover condition is met, the serving base station determines whether the current load of the target base station is overloaded; and when it is determined that the current load of the target base station is not overloaded, the serving base station hands over the user equipment to the target. base station.

100:Wireless communication system

102: User equipment

104:First Cell

106:Second cell

108:First base station

110:Second base station

112:Core network

S202~S220: steps

300:Device

302: Processor

304: Memory

306:Transceiver

Figure 1 is a schematic diagram of a wireless communication system according to an embodiment of the present invention.

Figure 2 is a flow chart of a method for managing handover according to an embodiment of the present invention.

FIG. 3 is a block diagram of a device for managing handover according to an embodiment of the present invention.

Through the following detailed description of specific embodiments in conjunction with the accompanying drawings, one can easily understand the above content and many advantages of this invention.

Please refer to FIG. 1 , which is a schematic diagram of a wireless communication system 100 according to an embodiment of the present invention. The wireless communication system 100 includes a user equipment 102, a first cell 104, a second cell 106, a first base station 108 that manages the first cell 104, and a second base station 110 that manages the second cell 106. The wireless communication system 100 also includes a core network 112 that communicates with the first base station 108 and the second base station 110 . In one embodiment, the first cell 104 includes a New Radio (NR) cell, the first base station 108 is a serving base station (gNB) of the user equipment 102, and the second cell 106 includes a fourth generation long-term evolution (4G/LTE) ) cell, the second base station 110 is a target base station (eNB) located near the user equipment 102. In the wireless communication system 100, the user equipment 102 may change hands between the first base station 108 and the second base station 110, and both the first base station 108 and the second base station 110 may become the serving base stations of the user equipment 102.

Please refer to FIG. 2 , which is a flow chart of a method for managing handover in the wireless communication system 100 according to an embodiment of the present invention. It should be noted that even if one or more blocks (or steps) are added to or removed from the process 200, the basic logical flow of this embodiment will not change; as long as there is no contradiction, the blocks of this embodiment The order (or steps) may also vary and is not limited to the specific order shown in Figure 2.

Step S202: The serving base station (for example, the first base station 108 in Figure 1) receives a measurement report from the user equipment (for example, the user equipment 102 in Figure 1). The measurement report includes channel quality indicator (Channel Quality Indicator, CQI) and bit error rate (Bit Error Rate, BER). In one embodiment, the user equipment calculates BER by dividing the number of error bits received within a certain period of time by the total number of bits received. In an embodiment, the user equipment can send measurement reports in periodic reporting mode and aperiodic reporting mode. In the periodic reporting mode, the user equipment periodically sends measurement reports according to the time period set by the serving base station. In the aperiodic reporting mode, the user equipment is triggered by the serving base station's trigger signaling to send the measurement report. In another embodiment, the measurement report only includes BER. The user equipment sends the measurement report and the CQI report simultaneously in periodic reporting mode and aperiodic reporting mode.

Step S204: The serving base station obtains a modulation and coding scheme (MCS) value according to the received CQI value. In an embodiment, a formula calculation or a preset mapping table may be used to obtain the MCS value according to the received CQI value.

Step S206: The serving base station receives a Reference Signal Received Power (RSRP) report from the user equipment. The RSRP report includes the RSRP of the serving base station and the RSRP of the target base station (for example, the second base station 110 in Figure 1).

Step S208: The serving base station determines whether the received BER is greater than the preset BER threshold. If the serving base station determines that the received BER is greater than the preset BER threshold, step S210 is executed; otherwise, step S218 is executed. In one embodiment, the BER of any user equipment should be maintained below a preset BER threshold. In this embodiment, the preset BER threshold can be set to, for example, 10%, which is 0.1.

Step S210: The serving base station determines whether the user equipment meets handover conditions. In one embodiment, the serving base station determines whether the user equipment meets the handover condition based on the received RSRP report, where the handover condition is that the RSRP of the target base station is greater than the RSRP of the serving base station plus the handover threshold. In an embodiment, when the user equipment meets the handover condition, the user equipment sends the RSRP report to the serving base station. In one embodiment, the serving base station uses the following formula to determine whether the user equipment meets the handover conditions:

RSRP _T >(RSRP _S +HO _TH ), where RSRP _T is the RSRP of the target base station, RSRP _S is the RSRP of the serving base station, and HO _TH is the handover threshold.

If the serving base station determines that the user equipment meets the handover conditions, step S212 is executed; otherwise, step S218 is executed.

Step S212: The serving base station determines whether the user equipment continues to meet the handover conditions within a preset time period. In one embodiment, the preset time period is set as a trigger time (Time-TO-Trigger, TTT) value. If the serving base station determines that the user equipment continues to meet the handover conditions within the preset time period, step S214 is executed; otherwise, step S218 is executed. In one embodiment, when the user equipment meets the handover conditions for the first time, the serving base station starts a timer to count the TTT value, and when the timer expires, determines whether the user equipment still meets the handover conditions. In specific application environments, this step can avoid the ping-pong effect during hand changing.

In one embodiment, the handover threshold and TTT value can be set based on empirical data. For example, operators can test wireless communication systems and set handover thresholds and TTT values based on specific situations/operating conditions.

Step S214: The serving base station determines whether the current load of the target base station is overloaded. In one embodiment, the serving base station determines whether the current load of the target base station is overloaded based on the load information reported by the target base station. The load message includes the radio resource occupation status of the target base station. In one embodiment, the load information also includes the spectrum occupancy rate, the number of user equipments served, the resource idle rate, and the corresponding capacity of the reserved resources. If the serving base station determines that the current load of the target base station is overloaded, step S216 is executed; otherwise, step S220 is executed.

Step S216: The serving base station reduces the MCS value.

Step S218: The serving base station allocates resource blocks to the user equipment according to the MCS value. In one embodiment, the serving base station looks up one or more tables based on the MCS value to determine the size of the transport block and the number of resource blocks. In practice, the one or more tables may be configured according to one or other LTE standards.

Step S220: The serving base station and the target base station perform handover of user equipment. Specifically, the serving base station hands over the user equipment to the target base station.

Please refer to FIG. 3 , which is a block diagram of a device 300 for managing handover in an embodiment of the present invention.

Apparatus 300 includes processor 302, memory 304, and transceiver 306. The processor 302 includes a microcontroller, a microprocessor, a complex instruction set computing microprocessor, a reduced instruction set computing microprocessor, a very long instruction set computing microprocessor, a super-parallel instruction set computing microprocessor, and any other computing processing device. capable digital signal processor or other circuit. The processor 302 is used to implement the method disclosed in the present invention. Memory 304 includes read-only memory, random access memory, magnetic storage media devices, optical storage media devices, flash memory devices, electrical, optical, or other computer-readable storage media, including physical/tangible and non-transitory devices. The memory 304 is coupled to the processor 302 to store one or more computer programs that control the operation of the device 300 and are executed by the processor 302 . Transceiver 306 is coupled to processor 302 for sending and/or receiving radio signals.

In summary, the methods and devices used to manage handover, and the addition of BER as a handover condition for signal quality, can allow the serving base station to more accurately determine whether the user equipment needs to be handed over. At the same time, the serving base station will consider the characteristics of the target base station. In the load state, if the target base station is in an overloaded state, the serving base station first maintains the throughput by reducing the MCS value, so that the user equipment is less likely to compete for the resources of the target base station, thereby improving the overall throughput in the wireless communication system.

It is worth noting that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solution of the present invention can be carried out. Modifications or equivalent substitutions may be made without departing from the spirit and scope of the technical solution of the present invention.

S202~S220: steps

Claims (6)

A method for managing handover in a wireless communication system. The method includes the following steps: a serving base station receives a measurement report from a user equipment, wherein the measurement report includes a channel quality indicator and a bit error rate; the serving base station Determine whether the bit error rate is greater than a preset bit error rate threshold; when it is determined that the bit error rate is greater than the preset bit error rate threshold, the serving base station determines whether the user equipment meets the requirements for handover Condition; when it is determined that the user equipment satisfies the handover condition, the serving base station determines whether the user equipment continues to satisfy the handover condition within a preset time period; when it is determined that the user equipment is in the preset time period, Assume that when the handover condition is continuously satisfied within the time period, the serving base station determines whether the current load of the target base station is overloaded; when it is determined that the current load of the target base station is not overloaded, the serving base station switches the user equipment. Go to the target base station; the serving base station determines and obtains a modulation and coding scheme (MCS) value based on the channel quality index; and when it is determined that the current load of the target base station is overloaded, the serving base station The base station reduces the MCS value and allocates resource blocks to the user equipment according to the MCS value. The method according to claim 1, wherein the method further includes the following steps: the serving base station receives a Reference Signal Received Power (RSRP) report from the user equipment, wherein the RSRP report Including the RSRP of the serving base station and the RSRP of the target base station. The method of claim 2, wherein the handover condition includes that the RSRP of the target base station is greater than the RSRP of the serving base station plus a handover threshold. A device for managing handover in a wireless communication system, wherein the device includes: a processor; and a memory for storing at least one computer program, wherein the computer program includes instructions executed by the processor, such that The processor performs the following steps: the serving base station receives a measurement report from the user equipment, where the measurement report includes a channel quality indicator and a bit error rate; the serving base station determines whether the bit error rate is greater than a predetermined Set a bit error rate threshold; when it is determined that the bit error rate is greater than the preset bit error rate threshold, the serving base station determines whether the user equipment satisfies the handover condition; when it is determined that the user equipment satisfies the handover condition; When the handover condition is mentioned above, the serving base station determines whether the user equipment continues to satisfy the handover condition within the preset time period; when it is determined that the user equipment continues to satisfy the handover condition within the preset time period. When conditions are met, the serving base station determines whether the current load of the target base station is overloaded; when it is determined that the current load of the target base station is not overloaded, the serving base station hands over the user equipment to the target base station; the service The base station determines and obtains a Modulation and Coding Scheme (MCS) value based on the channel quality index; and when it is determined that the current load of the target base station is overloaded, the serving base station reduces the MCS value and allocates resources according to the MCS value. block to the user equipment. The device of claim 4, wherein the processor further performs the following steps: the serving base station receives a Reference Signal Received Power (RSRP) report from the user equipment, wherein the RSRP The report includes the RSRP of the serving base station and the RSRP of the target base station. The apparatus according to claim 5, wherein the handover condition includes that the RSRP of the target base station is greater than the RSRP of the serving base station plus a handover threshold.

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