WO2005039224A1

WO2005039224A1 - A method of the ms handover

Info

Publication number: WO2005039224A1
Application number: PCT/CN2004/001110
Authority: WO
Inventors: Bing Xu
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2003-10-16
Filing date: 2004-09-28
Publication date: 2005-04-28
Also published as: CN1607856A; CN100441021C

Abstract

The present invention relates to the handover of the mobile communication system, and discloses a method of the MS 1 handover, which causes the delay of the MS handover reduce and the process of the BSC process the handover simple, and allow the MS to propose voluntarily the handover request. such method of MS handover comprising the follow steps: the MS measures the parameters than is need in the handover arithmetic, and calculates the measured results according to the handover arithmetic; said MS judges whether need to handover according to the measured results, if yes, the MS send handover request message to the network side; said network side responds to the handover request message from the MS, and performs handover.

Description

Mobile station cell switching method TECHNICAL FIELD

The present invention relates to cell switching in a mobile communication system, and in particular, to a method for a mobile station to switch between different cells in a mobile communication system. BACKGROUND In recent years, communication technology, especially mobile communication technology, has been greatly developed. With the successive introduction of the first to third generation mobile communication systems, the impact of mobile communication on human life and work is increasing. The second-generation mobile communication system, which has been widely used around the world, and the third-generation mobile communication system, which will soon be used on a large scale, are all based on cellular mobile communication systems. Frequency reuse in cellular technology greatly improves frequency utilization and increases the capacity of a communication system. Among them, handover, as an advantage in cellular technology, greatly expands the service range of a communication network. Handover refers to transferring a mobile station (Mobile) (referred to as "MS") in a call establishment state or a busy state to a new service channel, the purpose of which is to continue to maintain the mobile station's call when the serving cell changes, Or, perform channel switching when the current serving cell or channel interference is large to ensure the balance of inter-cell services. The following describes the cell handover process in the prior art by taking a Global System for Mobile Communication (abbreviated as "GSM") as an example with reference to FIG. 1. As shown in FIG. 1, in step 100, a base transceiver station (Base Transceiver Station ("BTS" for short) notifies mobile stations ("MS" for short) to measure information about BTSs in their surrounding cells, as well as the carrier frequency, signal strength, and broadcast strength of the broadcasting control channel ("BCCH") for the MS. The signal strength and transmission quality of the occupied traffic channel (Traffic Channel, "TCH" for short). Thereafter, it proceeds to step 2GG, and the MS performs measurement according to the above instruction. After that, step 300 is performed. After the MS finishes the measurement, the measurement result is sent to a base station controller (Base Station Controller, "BSC" for short). After that, the process proceeds to step 400, and the BSC compares and queues the surrounding cells according to the measurement result, determines whether a handover is required, and determines the time for handover and which BTS to handover to. The handover mentioned above to ensure the inter-cell service balance means that the MS is talking in the coverage overlap area of the two cells, but the service of the occupied TCH is busy than the other cell, and the BSC notifies the MS Measure the signal strength and channel quality of another cell, and decide whether to switch the MS to another cell based on the measurement results. The main process is the same as the flowchart shown in FIG. 1. It should be noted that although the technical problems, technical solutions, and technical effects are described in terms of GSM in the present invention, the present invention can also be applied to other second generations such as Code Division Multiple Access (Code Division Multiple Access, referred to as "CDMA") Communication system, or third-generation mobile communications (Wideband Code Division Multiple Access, "WCDMA" for short), etc. Those skilled in the art of the present invention will understand that The components of the communication system mentioned in the solution of the present invention are There are corresponding components in various mobile communication systems, for example, MS in GSM corresponds to UE in 3G, BTS in GSM corresponds to NodeB (Node B) in 3G, and BSC in GSM and wireless in 3G Corresponding to a network controller (Radio Network Controller, abbreviated as "RNC"), and so on. In practical applications, the above solution has the following problems: First, the processing in the handover process is very complicated. Specifically, in the above process, the MS reports the channel shield measurement results of the cell in which it is located and the neighboring cells to the BSC. Therefore, for the BSC, there are a large number of measurement results from the MS, so the BSC processing is very complicated. Second, the switching delay is large. Because the MS reports the measurement result to the BSC and waits for the BSC to process it, there is a certain delay during this period. The source of this delay can be the delay of the wireless communication link between the MS and the BSC, or it can be the BSC because it needs to be processed at a certain time. Too much data is too late to be processed and the delay caused.

Third, in the above process, since the current protocol does not support it, the MS is not allowed to initiate a handover request according to its specific situation. SUMMARY OF THE INVENTION The technical problem to be solved by the present invention is to provide a mobile station cell handover method, which reduces the mobile station cell handover delay, the base station controller's processing process for the handover is simplified, and allows the mobile station to make a handover request autonomously. In order to solve the above technical problems, the present invention provides a mobile station cell switching method, including the following steps: B The mobile station measures the parameters required for cell handover;

C. The mobile station determines whether a handover is required according to the measurement result, and if so, sends a handover request message to the network side;

D. The network side performs cell handover in response to the handover request message of the mobile station. The method further includes:

A The network side notifies the mobile station to measure parameters required in the handover algorithm. The method further includes the network side notifying the mobile station to perform parameter measurement. The mobile station periodically measures cell handover parameters. In step C, if the mobile station determines that a handover is not required according to the calculation result, it does not send a message related to the handover to the network side. In step D, the base station controller of the network side responds to the handover request message of the mobile station. In step D, the radio network controller of the network side responds to the handover request message of the mobile station. The parameters required in the handover algorithm include any combination of one or more of reception quality, reception level, distance between the mobile station and the base station, and power headroom related to the reception level. The handover request message further includes the following parameters: Message type, handover reason, and destination cell information. The method further includes presetting parameter thresholds required for cell switching, so that the mobile station determines in step C whether cell switching is required. It can be found from the comparison that the technical solution of the present invention is different from the prior art in that the determination of the cell handover of the mobile station originally performed in the BSC is transferred to the MS for execution. The MS no longer sends the measurement data required for cell handover to the BSC, but directly determines whether a handover is needed. If a handover is required, it sends a handover request to the BSC, and the BSC performs handover processing according to the received request.

This technical solution difference brings a more obvious beneficial effect, that is, by moving the judgment of the switching decision to the MS, the processing load of the BSC will be significantly reduced, and the cost of the BSC will be greatly reduced. The MS can make handover decisions in real time according to the corresponding processing, thereby avoiding the problem of excessive delay caused by BSC processing. The MS does not need to transmit a large amount of measurement data to the BSC, which saves wireless communication bandwidth. In certain situations, the MS can initiate a handover request according to its own situation. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flowchart of a mobile station cell handover in the prior art; FIG. 2 is a flowchart of a mobile station cell handover method according to an embodiment of the present invention;

FIG. 3 is a flowchart of a handover determination in a mobile station cell handover method according to an embodiment of the present invention. DETAILED DESCRIPTION To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in further detail below with reference to the accompanying drawings. During the handover process, there are multiple determining factors that cause the handover, such as the reception quality, the reception level, the distance between the MS and the BST, and the power headroom related to the reception level. According to the above-mentioned cell handover factors, it can be determined whether a cell handover is required through judgment. Therefore, according to an embodiment of the present invention, as shown in FIG. 2, the first step 210 is to notify the MS of measurement related information by the BTS. The information includes the radio link connection quality of the current serving cell and the neighbor cell's The reception level, the distance between the mobile station and the base station, and the power headroom related to the reception level. In other embodiments of the present invention, the mobile station measures cell handover parameters and initiates the timing autonomously. At this time, a timer and a timing interval need to be set in advance. After that, the process proceeds to step 220, and the MS responds to the BTS command to measure the relevant value. Next, the method proceeds to step 230. The MS processes the measurement result, for example, stores the result, and calculates an average value of the stored result multiple times, so as to determine whether a cell handover is required according to the average value. However, in this example, a single measurement result is used to determine whether a cell handover is required. Then it proceeds to step 240, and the MS judges whether to switch according to the output of the algorithm. When it is determined that the switching is not required, it proceeds to step 250, that is, no information is sent, and the process ends; if it is determined that the switching is required, it proceeds to step 260. Algorithm and prior art in this step The algorithm performed in BSC is the same. Specifically, as shown in FIG. 3, in an embodiment of the present invention, step 240 includes the following sub-steps: Step 241: Determine whether the reception quality meets a handover condition. That is, whether the calculation result satisfies the following conditions, and whether the receiving quality meets the handover condition is determined by the following conditions 1, 2, and 3:

1. RXQUAL-XX> L_RXQUAL_XX-H;

2. RXLEV—XX <L-RXLEV-XX- IH;

3. XX-TXPWR = Min (XX_TXPWR_MAX, P); where RXQUAL is the receiving quality, XX is a variable with the value of UL (uplink) or DL (downlink), and RXQUAL_XX is the uplink / downlink Receiving quality, L_RXQUAL_XX_H is the uplink / downlink quality threshold, RXLEV-XX is the measured average value of the receiving level of the serving cell, L-RXLEV— XX—IH is the receiving level threshold, and XX—TXPWR is the transmission of the mobile station in the serving cell Power, XX-TXPWR-MAX refers to the maximum allowable transmission power of the mobile station in the serving cell, P refers to the maximum power of the mobile station itself, and Min (XX_TXPWR_MAX, P) is a value between XX_TXPWR_MAX and P takes a smaller value between the two. If it is determined that the above conditions are satisfied at the same time, a switchover (quality-based switchover) is required, that is, step 246. Otherwise proceed to step 242. In step 242, it is determined whether the reception level satisfies a switching condition. I.e. the calculation result is If the following conditions are met, the following conditions 1 and 2 are used to determine whether the receiving level meets the switching conditions:

1. RXLEV-XX <L-RXLEV-XX-H;

2. XX-TXPWR = Min (XX—TXPWR— MAX, P); where L— RXLEV— XX— H is the uplink / downlink level threshold. If it is determined that the above conditions are met at the same time, a switchover (switchover caused by the reception level) is required, that is, step 246. Otherwise proceed to step 243. In step 243, it is determined whether the distance between the MS and the BST satisfies the handover condition. That is, whether the calculation result satisfies the following conditions: MS-BS-DIST> MS-RANGE- MAX where MS-BS-DIST is the distance between MS and BTS, and MS-RANGE-MAX is the gate of maximum distance between MS and BTS Limit. If it is determined that the above conditions are met, a handover (a distance-based handover) is required, that is, step 246. Otherwise proceed to step 244. In step 244, it is judged whether the power headroom meets the switching condition, that is, whether the calculation result satisfies the following conditions, and the judgment of whether the power headroom meets the switching condition is implemented through the following conditions 1, 2:

1. RXLEV— NCELL (n)> RXLEV—MIN (n) + Max (0, MS_TXPWR_MAX (n)-P); 2. PBGT (n)> HO— MARGIN (n); where RXLEV_NCELL (n) is the receiving level in the neighboring cell n, and RXLEV.MIN (n) is the minimum receiving level threshold in the neighboring cell n. MS-TXPWR_MAX (n) is the maximum transmit power allowed by the mobile station in the neighboring cell n, and Max (0, MS-TXPWR-MAX (n)-P) is taken between 0 and MS_TXPWR — MAX (n)-P A maximum value, PBGT (n) is the path margin of the serving cell minus the path loss of the neighboring cell n, and H0_MARGIN (n) is the path loss of the serving cell minus the path loss of the neighboring cell n. Threshold. If it is determined that the above conditions are met simultaneously, a handover (a handover caused by a power headroom) is required, that is, step 246. Otherwise, it is determined that no handover is required, that is, step 245. It should be noted that the parameter thresholds required for the above cell switching, for example, L-RXLEV_XX_H, L_RXQUAL_XX_H, etc. need to be set in advance. In step 260, the MS sends a handover request message to the BSC, and the request message includes parameters such as a message type, a handover reason, and a destination cell of the handover. Thereafter, the process proceeds to step 270, and the BSC responds to the handover request message of the MS and performs handover processing. Although the present invention has been illustrated and described by referring to certain preferred embodiments of the present invention, those skilled in the art should understand that Various changes may be made in form and detail without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

Rights request

A method for handover of a mobile station cell, comprising the following steps:

B The mobile station measures the parameters required for cell handover;

D. The network side performs cell handover in response to the handover request message of the mobile station.

2. The mobile station cell switching method according to claim 1, further comprising the following steps:

A The network side notifies the mobile station to perform parameter measurement.

3. The mobile station cell switching method according to claim 1, wherein the mobile station periodically measures the cell switching parameters.

4. The mobile station cell switching method according to claim 1, 2 or 3, characterized in that, in the step C, if the mobile station determines that no handover is needed based on the calculation result, it does not send to the network side Messages related to switching.

5. The method for handover of a mobile station cell according to claim 1, 2 or 3, characterized in that, in the step D, the base station controller of the network side responds to the handover request message of the mobile station.

6. The mobile station cell switching method according to claim 1, 2 or 3, characterized in that in said step D, a radio network controller of said network side responds to said mobile Station handover request message.

7. The method for handover of a mobile station cell according to claim 1, 2 or 3, wherein the parameters include reception quality, reception level, distance between the mobile station and the base station, and power headroom related to the reception level Any combination of one or more of them.

8. The method for mobile station cell handover according to claim 1, 2 or 3, wherein the handover request message further includes the following parameters: message type, handover reason and target cell information for handover.

9. The cell switching method for a mobile station according to claim 1, 2 or 3, further comprising: presetting a parameter threshold required for cell switching, and step C determines whether cell switching is required according to the parameter threshold.