CN100359989C - A method for setting user equipment activation time offset - Google Patents

Abstract

The present invention discloses a method for activating time offset with user equipment, which is applied to a wireless communication system for determining the activation time of user equipment. The present invention comprises the procedures: a value which influences the reference index of oral signaling transmission efficiency is obtained; the current oral signaling transmission efficiency of a wireless communication system is determined according to the reference index, and activation time offset is selected according to the current oral signaling transmission efficiency. The method of the present invention can dynamically set the activation time offset according to the specific condition of network environments.

Description

A method for setting user equipment activation time offset

technical field

The invention relates to the field of wireless communication, in particular to a method for setting user equipment activation time offset through air interface signaling.

Background technique

The Universal Mobile Telecommunications System Air Interface (Uu, UMTSAir Interface) signaling process of the Wideband Code Division Multiple Access (WCDMA) system requires the user equipment (UE, User Equipment) to switch to a specific configuration at a specific time, and the specific time is called As the "activation moment", the "activation moment" is configured to the UE by the Universal Mobile Telecommunications System Terrestrial Radio Access Network (UTRAN, UMTS Terrestrial Radio AccessNetwork) through the Uu interface signaling (because the Uu interface signaling transmission requires a certain amount of time, so Usually, the UTRAN selects the activation time offset and sends the Uu interface signaling carrying information related to the activation time offset, and the UE switches the configuration at the activation time after receiving the Uu interface signaling). The Uu interface signaling may be radio bearer (RB, Radio Bearer) establishment signaling, RB reconfiguration signaling, transport channel reconfiguration signaling, physical channel reconfiguration signaling, and the like. According to the provisions of the protocol 3GPP TS25.33 1, the value of the activation time can be "immediate activation" ("Now"), or it can be determined by the connection frame number (CFN, Connection Frame Number) with a value range of (0-255). )express.

An existing technology for selecting the activation time of the user equipment is: divide the transmission quality of a specific WCDMA wireless network into three levels, and the three levels require different activation time offsets ΔT, namely ΔT1, ΔT2, ΔT3 . For the same network setting, the values of ΔT1, ΔT2, and ΔT3 are fixed. In the actual value selection process, in order to take into account the success rate of the signaling process under the quality of most signaling transmissions, the network only needs to use the values from ΔT1, ΔT2, and ΔT3. Among them, the largest one is selected as the activation time offset ΔT for each allocation. Under normal network conditions, the value of ΔT is between 1 second and 2 seconds. The protocol specifies a maximum value of 2.56 seconds for ΔT.

The disadvantage of the above method of setting the time offset is: for the same network, the set activation time offset ΔT is fixed, and it will not be dynamically adjusted in real time with different network quality, resulting in relatively Due to different network qualities, the activation time offset is set too large or too small, which brings some defects. This is because the transmission of Uu interface signaling requires a certain amount of time, and in the case of a certain bit error rate, Uu interface signaling may also have bit errors that cause the receiver to fail to parse, thus requiring the radio network controller (RNC, Radio Network Control) retransmits the corresponding signaling unit, and the Uu interface transmission delay of the signaling will increase with the increase of the retransmission rate of the signaling unit. The interface signaling including the activation time offset sent by the network to the UE is also affected by the above bit error rate when transmitted through the Uu interface. When the bit error rate of the Uu interface is constant, it is inappropriate for the time offset between the activation time and the current time (the time when the UTRAN notifies the UE of the activation time signaling) to be too large or too small.

If the activation time offset is too large, it will cause the user equipment to wait too long for the configuration to take effect, which will increase the delay of all signaling processes including the activation time, such as service establishment, service modification, and handover.

Please refer to FIG. 1 , taking the RB establishment process as an example to illustrate the impact of an excessively large activation time offset on the signaling process. The RNC side divides the RB Setup message (RB Setup) into several data packets and sends them to the UE side in turn. T1 represents the moment when the RNC sends the first data packet of the RB Setup message, and T2 represents the time when the last data packet of the RBSetup message arrives at the UE. time, the activation time indicated by the RB Setup message is (T1+ΔT), where ΔT is the activation time offset.

If (T1+ΔT) is greater than T2, after receiving the RB Setup message, the UE must wait for (T1+ΔT-T2) time to apply the configuration information specified by the RB Setup message, and then respond to the RNC with a radio bearer establishment complete message (RB Setup Complete ). The larger ΔT is, the longer the UE waits before applying the new configuration, and the later the RNC receives the RB Setup Complete message.

For the case where the activation time offset is too small, when the activation time configured by the network has arrived, the Uu interface signaling containing the activation time information may still be in an intermediate link of the Uu interface downlink data transmission channel and has not yet fully arrived. UE. Since the configurations of the general network and the UE before and after the activation time are different, the network will switch to the configuration after the activation time when the activation time is reached; however, the UE has not received the complete Information signaling) and still in the configuration before the activation time, so the configurations of the network and the UE are inconsistent at this time, and the UE cannot continue to receive any downlink signaling, so the configuration before the activation time is deadlocked, and the network may not be able to Receiving any uplink signaling sent by the UE will eventually lead to a complete interruption of the uplink and downlink data transmission between the network and the UE.

Please refer to FIG. 2 , taking the RB establishment process as an example to illustrate the influence of too small activation time offset on the signaling process. If (T1+ΔT) is less than T2, the RNC switches to the new configuration at (T1+ΔT) and continues to send the remaining data packets of the RB Setup message according to the new configuration, and the UE can only complete the RB Setup message according to the RB Setup message. The content of the Setup message obtains the configuration information after the activation time, so the UE will not be able to parse the data packets of the RB Setup message received after the (T1+ΔT) time, and thus cannot reassemble the RB Setup message, resulting in the failure of subsequent processes , and the network cannot receive the UE's RB Setup Complete message. Therefore, the RB Setup process failed this time.

To sum up, when (T1+ΔT) is equal to T2, the minimum time delay can be obtained on the premise of ensuring the success of the signaling process. However, this is only an ideal situation. Due to the wide variety of network conditions in the actual network, the signaling transmission quality between the RNC and the UE also varies widely, and it is difficult to determine the time T2 when the message sent by the RNC reaches the UE. The worse the signaling transmission quality between the RNC and the UE is, the larger the T2 is obviously, and vice versa. Therefore, it is obvious that there are deficiencies in the prior art using a fixed activation time offset.

Contents of the invention

In order to overcome the defects caused by the fixed activation time offset in the prior art, the technical problem solved by the present invention is to provide a method for setting the activation time offset of the user equipment, which can dynamically set the activation time according to the specific conditions of the network environment offset.

The technical solution used by the present invention to solve the technical problem is to provide a method for selecting the activation time offset of the user equipment, which is applied to a wireless communication system to determine the activation time of the user equipment; including steps:

1) Obtain the block error rate of the transmission channel;

2) According to the block error rate of the transmission channel, determine the number of wireless link control retransmissions;

3) Estimating the current air interface signaling transmission efficiency according to the number of wireless link control retransmissions;

4) According to the current air interface signaling transmission efficiency, estimate the time overhead of the successful transmission of the current signaling on the air interface;

5) Select an activation time offset according to the transmission time overhead.

The present invention also provides another method for selecting the activation time offset of the user equipment, which is applied to a wireless communication system to determine the activation time of the user equipment; including steps:

a) Obtain the value of the flow rate of the channel as a percentage of the total flow rate;

b) determining the currently available remaining bandwidth percentage of the wireless communication system according to the percentage value;

c) Obtain the activation time offset according to the current available remaining bandwidth percentage.

Compared with the prior art, the beneficial effects of the present invention are: because the present invention first obtains the value of the reference index that affects the transmission efficiency of air interface signaling, and estimates the current air interface signaling transmission efficiency of the wireless communication system accordingly, and then based on the air interface signaling Selecting the activation time offset for the transmission efficiency can overcome to the greatest extent the disadvantages caused by the fixed activation time offset setting in the existing technology, which causes the activation time to be too large or too small, thereby reducing the delay of the signaling process, Improve the success rate of the signaling process.

Description of drawings

Figure 1 is a schematic diagram when the activation time offset is set too large;

Fig. 2 is a schematic diagram of setting the activation time offset too small;

FIG. 3 is a flowchart of a method for setting user equipment activation time offsets according to the present invention;

FIG. 4 is a schematic diagram of the inter-layer relationship of the air interface signaling transmission process;

Fig. 5 is a flow chart of setting an activation time offset by using a block error rate of an uplink transmission channel according to an embodiment of the present invention.

Detailed ways

The method for setting the user equipment activation time offset of the present invention dynamically adjusts the time offset between the activation time configured by the network to the UE each time and the current time, determines the current air interface signaling transmission efficiency according to the current network environment, and real-time Dynamically adjust the activation time offset, so as to overcome the disadvantages caused by too large or too small activation time offset to the greatest extent.

Referring to FIG. 3, the method for setting the user equipment activation time offset of the present invention includes:

Step S1, acquiring the value of a reference index that affects air interface signaling transmission efficiency.

In actual networks, the reference indicators that affect the transmission efficiency of air interface signaling mainly include: transmission channel block error rate, physical channel bit error rate, transmission channel bandwidth, physical channel bandwidth, distance between base station and mobile phone, etc. Among them, the bit error rate of the physical channel and the block error rate of the transmission channel have similar meanings. Although the former is an index of the physical channel and the latter is the index of the transmission channel, the method of estimating the transmission efficiency of air interface signaling by using the bit error rate of the physical channel is the same as that of using the transmission channel The method of estimating air interface signaling transmission efficiency by block error rate is similar. The channel bandwidth includes transmission channel bandwidth and physical channel bandwidth, because the transmission channel is mapped on the physical channel, so the two are basically consistent in change trend.

Step S2, according to the aforementioned reference index, determine the current air interface signaling transmission efficiency of the wireless communication system.

Please refer to FIG. 4 , which is a schematic diagram of the relationship between layers of the air interface signaling transmission process.

Wherein, the radio resource control layer message (RRC, Radio Resource Control) refers to the air interface signaling between the RNC and the UE. When the RRC signaling is sent, it is first divided into one or more radio link control layer transmission blocks (RLC PDU, Radio Link Control Protocol Data Unit), and the RLC layer communication between the RNC and the UE is performed through the RLC PDU; each Each RLC PDU will be divided into one or more medium access control layer protocol data units (MAC PDU, Medium Access Control Protocol Data Unit), which are sent after multiple transmission time intervals (TTI) for the MAC layer between RNC and UE communication.

According to the CRC (Cyclic Redundancy Code) check flag of each MAC PDU, the MAC judges whether the PDU has a CRC check error, and the MAC PDU (especially the data block of the RRC signaling) with a CRC check error is discarded. PDUs are considered invalid and will be discarded. An error in the MAC PDU will result in the inability to reassemble and restore the corresponding RLC PDU, and then the RLC cannot reassemble and restore the RRC signaling. Therefore, RLC needs to retransmit RLC PDUs that MAC cannot reassemble and recover due to block errors. When the RLC works in the confirmation mode, the RLC numbers each PDU sequentially, and the wrong PDU of the MAC will cause the sequence numbers of the PDUs received by the RLC to be inconsistent, and the retransmission mechanism of the RLC will retransmit the missing PDUs.

Since MAC PDU errors may also occur during RLC retransmission, it can only be said that RLC retransmission can increase the probability of receiving missing RLC PDUs. The more retransmissions, the greater the probability of successfully receiving missing RLC PDUs. Since it takes a certain amount of time for data to be sent and received through the air interface, the retransmission will double the time delay for the RLC to successfully recombine and recover the air interface signaling, reducing the transmission efficiency of the air interface signaling. Therefore, the larger the uplink BLER (Block Error Rate), the more RLC PDU retransmission times; the larger the BLER, the lower the success probability of RLC PDU retransmission, and the lower the air interface signaling transmission efficiency.

In the case of the transmission channel block error rate of 1% generally configured in the industry (the corresponding physical channel bit error rate is less than 1%), due to the random occurrence of bit errors in the wireless communication system, some or all of these transmission blocks may Unable to parse due to bit errors. The RLC reliability guarantee mechanism can retransmit these unparsable data blocks, so as to finally improve the transmission success rate of air interface signaling.

On the premise of ensuring successful air interface signaling transmission, the higher the block error rate of the transmission channel or the bit error rate of the physical channel, the higher the average number of retransmissions of the RLC is required. The time overhead caused by RLC retransmission is proportional to the number of RLC retransmissions. Therefore, the higher the block error rate of the transmission channel or the bit error rate of the physical channel, the greater the average time overhead required for successful air interface signaling transmission.

The meaning of the bit error rate of the physical channel is similar to that of the block error rate of the transmission channel. The method of estimating the signaling transmission efficiency of the air interface by using the bit error rate of the physical channel is similar to the method of estimating the signaling transmission efficiency by using the block error rate of the transmission channel.

The channel bandwidth includes the transmission channel bandwidth and the physical channel bandwidth. The channel bandwidth determines the maximum capability of transmitting air interface data per unit time, and is proportional to the transmission delay of signaling on the air interface.

The distance between the base station and the mobile phone also affects the transmission efficiency of the air interface signaling. The distance between the base station and the mobile phone determines the propagation time of the air interface radio wave, so the transmission delay of the air interface signaling also depends on the distance between the base station and the mobile phone. increase or decrease with the increase or decrease of the distance.

In step S3, an activation time offset is selected according to the current air interface signaling transmission efficiency.

Firstly, according to the transmission efficiency of the current air interface, the time overhead required for the successful transmission of signaling through the air interface is estimated; secondly, under the premise of ensuring the success of the signaling process, according to the time overhead, the time delay of the signaling process is the smallest Set the activation time offset ΔT in principle.

It can be understood that whether the dynamic adjustment of the activation time offset is effective depends on whether the current air interface signaling transmission efficiency can be accurately estimated, and then the time overhead required for the current signaling to be successfully transmitted on the air interface can be estimated. For signaling with a certain length, the higher the transmission efficiency of the air interface, the less time it takes for the signaling to be successfully transmitted through the air interface; otherwise, the more time it takes.

Please refer to FIG. 5 , in a specific embodiment of the present invention, the block error rate of the uplink transmission channel is used as the basis for estimating the current air interface signaling transmission efficiency, and the user equipment activation time offset is determined according to the current air interface signaling transmission efficiency.

The flow process of the described embodiment is: first execute step S11, count the uplink BLER by the MAC of the RNC, and the BLER represents the block error rate of the uplink transmission channel, that is, the ratio of the number of uplink wrong transmission blocks to the total number of blocks of the uplink transmission channel .

Step S11 specifically includes: MAC judges whether CRC verification error occurs in the PDU according to the CRC check flag of each MAC PDU; if the CRC flag indicates that the CRC check is wrong, MAC then thinks that the PDU is an error block, and counts the number of error blocks ; The block error rate BLER of the uplink transmission channel is obtained by comparing the number of uplink transmission error blocks counted by the MAC with the total number of blocks of the uplink transmission channel.

Step S12, calculating the number of radio link control retransmissions according to the uplink BLER.

In step S12, the relationship between BLER, RLC PDU retransmission times, and RLC PDU retransmission success probability is as shown in formula (1):

$\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; x</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}^{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Where P represents the success probability of RLC PDU retransmission, x represents BLER, and N represents the number of RLC PDU retransmissions. According to formula (1), the higher the BLER, the lower the probability of successful RLC PDU retransmission, and vice versa, the higher the probability of successful RLC PDU retransmission.

When the BLER is constant, when the number of RLC PDU retransmissions N meets the requirements of formula (2), the reliable transmission of air interface signaling can be guaranteed:

Mx ^N <1...................(2)

Among them, M represents the number of MAC PDUs divided into air interface signaling, x represents BLER, and N represents the number of RLC retransmissions.

The following example illustrates the application of formula (2):

If air interface signaling includes 10 MAC PDUs and BLER is 10%, satisfying the above formula requires N>1. From the perspective of reducing air interface signaling transmission delay and improving air interface signaling transmission efficiency, the smaller N is, the better. Therefore , where N takes the value of 2.

Step S13, estimating the current air interface signaling transmission efficiency according to the RLC retransmission times, the more RLC retransmission times, the greater the air interface signaling transmission delay, the lower the air interface signaling transmission efficiency, and vice versa;

Step S14, estimating the time cost of successful transmission of the current signaling on the air interface according to the transmission efficiency of the air interface signaling.

If the time required for an RLC PDU to be sent and received on the air interface under ideal conditions is Tu, then the total time required after retransmitting N times is N×Tu.

Therefore, in the RLC PDU contained in the air interface message, the ratio of the number of transmission blocks that need to be retransmitted to the total number of transmission blocks, and the number of retransmissions of each RLC PDU determine the air interface signaling transmission efficiency, that is, determine the transmission efficiency of the air interface message. The total time required for air interface transmission, formula (3) gives a simplified estimation method of air interface message transmission time:

T2-T1=(M+N)Tu...................(3)

Where T1 represents the moment when the first data packet sent by the RNC, T2 represents the moment when the last data packet of the message arrives at the UE, (T2-T1) represents the time required for the message to be transmitted through the air interface, and the meanings of M and N refer to formula (2 )instruction of.

Step S15 , setting the activation offset time according to the time overhead of successful air interface transmission, and configuring the activation time offset to the UE.

For the aforementioned RB setup message containing the activation time offset ΔT, when the RNC is preparing to send the message, it first needs to calculate (T2-T1) according to formula (2) and formula (3), and then according to formula (4 ) to set ΔT:

ΔT≥T2-T1...................(4)

ΔT should be as small as possible while satisfying Formula 4, so as to ensure the success of the signaling process and reduce the system delay.

The above describes the method of using BLER to measure the transmission efficiency of air interface signaling and determine the activation time offset.

The present invention will be further described below in conjunction with the embodiment of selecting the activation time offset according to the channel bandwidth.

The channel bandwidth determines the maximum capability of transmitting air interface data per unit time. The transmission channel bandwidth and physical channel bandwidth are proportional to the transmission delay of signaling on the air interface. The channel bandwidth is controlled by the RNC, and the larger the channel bandwidth, the higher the signaling transmission efficiency. The channel bandwidth for carrying signaling can be divided into three levels. Level 1 corresponds to the downlink forward access channel (FACH) to carry signaling; level 2 corresponds to a dedicated channel (DCH) with a bandwidth of 3.4Kbps to carry signaling; level 3 corresponds to Use 13.6Kbps DCH to carry signaling.

The process of selecting the activation time offset is different when applying the three levels of channel bandwidth to carry signaling.

The process of setting the activation time offset when the FACH bears signaling is: the RNC side counts the FACH traffic in the current time; if the traffic statistics of the FACH is n% of the total traffic, the current available remaining bandwidth percentage is (1-n% ); set the activation time offset as ΔT/(1-n%), where ΔT is the corresponding activation time offset when the FACH traffic statistics is 0 under a certain transmission channel bit error rate.

Although the total bandwidth of the FACH channel is high, as a common transmission channel, it may be used by multiple user equipments in the cell at the same time, and the actual bandwidth obtained by each user equipment will be much smaller than the total bandwidth, which is determined by the load of the FACH. The higher the FACH load is, the lower the signaling transmission efficiency of the FACH is for a single user equipment; otherwise, the higher the signaling transmission efficiency of the FACH is. The RNC can obtain the FACH traffic statistics within a period of time in real time as a basis for measuring the FACH load.

If the bandwidth of FACH is exclusively shared by a single user equipment, that is, the traffic statistics of FACH for a period of time so far is 0, and in the case of a certain transmission channel bit error rate, the requirement for activation time offset is ΔT, then when When the flow statistics of the FACH are n% of the total flow, the requirement for the activation time offset is ΔT/(1-n%). That is, how many times the current available bandwidth is reduced relative to the total bandwidth, the required activation time offset is correspondingly increased by how many times.

Estimate the signaling transmission efficiency method when the bandwidth is 3.4Kbps DCH bears signaling and when the bandwidth is 13.6Kbps DCH bears signaling: the bandwidth of the DCH channel is exclusively shared by a single user equipment, and the signaling transmission efficiency estimation method is equivalent to "FACH bandwidth "The process of setting the activation time offset when FACH bears signaling" in "Exclusively for a single user equipment". The only difference is that the channel bandwidth is different and the bit error rate setting of the transmission channel will not be exactly the same. For the specific description of the estimation method, see The previous article will not be repeated here.

The distance between the base station and the mobile phone also affects the transmission efficiency of the air interface signaling. The distance between the base station and the mobile phone determines the propagation time of the air interface radio wave, so the transmission delay of the air interface signaling also depends on the distance between the base station and the mobile phone. increase or decrease with the increase or decrease of the distance. When the cell radius is not too large, the influence of the propagation time of radio waves on the transmission delay of air interface signaling is relatively small.

The above descriptions are only preferred embodiments of the present invention, and do not constitute a limitation to the protection scope of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (8)

1, a kind of method of selecting active time displacement of user equipment is applied to wireless communication system to determine the activationary time of subscriber equipment; It is characterized in that, comprise step:

1) obtains the transmission channel Block Error Rate;

2), determine Radio Link control number of retransmissions according to described transmission channel Block Error Rate;

3) estimate current space interface signaling efficiency of transmission according to Radio Link control number of retransmissions;

4), estimate that current signaling is in the success transmission time expense of eating dishes without rice or wine according to current space interface signaling efficiency of transmission;

5) select active time displacement according to described transmission time expense.

2, the method for selection active time displacement of user equipment as claimed in claim 1 is characterized in that: described step 2), adopt formula

Mx ^N＜1

Select the space interface signaling number of retransmissions; Wherein, M represents the divided number of space interface signaling, and x represents the transmission channel Block Error Rate, and N represents number of retransmissions.

3, the method for selection active time displacement of user equipment as claimed in claim 1 is characterized in that: in the described step 4), adopt formula

T2-T1＝(M+N)Tu

The decision time overhead; Wherein, T1 represents to send the moment of first packet of space interface signaling, T2 represents that last packet of space interface signaling arrives the moment of subscriber equipment, T2-T1 express time expense, M represents the divided number of space interface signaling, N represents number of retransmissions, and Tu representation unit transmission block is in the time of eating dishes without rice or wine transmission primaries.

4, a kind of method of selecting active time displacement of user equipment is applied to wireless communication system to determine the activationary time of subscriber equipment; It is characterized in that, comprise step:

A) flow that obtains channel accounts for the value of total flow percentage;

B), determine the current available remaining bandwidth percentage of wireless communication system according to described percent value;

C), obtain active time displacement according to current available remaining bandwidth percentage.

5, the method for selection active time displacement of user equipment according to claim 4 is characterized in that: described channel is descending use forward access channel.

6, the method for selection active time displacement of user equipment according to claim 4 is characterized in that: it is the dedicated channel of 3.4Kbps and 13.6Kbps that described channel is to use bandwidth.

7, according to the method for claim 4,5 or 6 described selection active time displacement of user equipment, it is characterized in that: in the described step b), adopt formula

1-n％

Determine the current available remaining bandwidth percentage of wireless communication system, wherein, n% represents that the flow of channel accounts for the value of total flow percentage.

8, according to the method for claim 4,5 or 6 described selection active time displacement of user equipment, it is characterized in that: in the described step c), adopt formula

ΔT/(1-n％)

Obtain active time displacement, wherein, Δ T is illustrated under the situation of certain transmission channel bit error rate and traffic statistics are the active time displacement of 0 o'clock correspondence.

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