CN101873673A - Double-radio-frequency interface scheduling method for fast switching - Google Patents

Abstract

The present invention relates to the field of wireless communication technology, and discloses a dual radio frequency interface scheduling method for fast switching, the method comprising: calculating and collecting measurement data of multiple intelligent triggers according to different layer metric values of a mobile terminal accessing a wireless network link, and obtaining a scanning decision value according to a multi-condition decision normalization algorithm; when the intelligent trigger is in a normal state, the mobile terminal performs intelligent trigger decision scanning according to the scanning decision value, otherwise, performs periodic scanning. The dual radio frequency interface scheduling method for fast switching disclosed by the present invention adopts alternate activation and deactivation of dual radio frequency interfaces to perform active scanning, and the method is applied in a mobile terminal to avoid unnecessary energy consumption, while not reducing the performance of fast switching.

Description

A dual radio interface scheduling method for fast switching

technical field

The present invention relates to the technical field of wireless communication, more specifically, to a scheduling method of dual radio frequency interfaces used for fast switching in a wireless network.

Background technique

With the development of wireless communication technology, the application based on wireless network has grown rapidly, and a large number of different types of mobile terminals have emerged, such as portable notebook computers, smart phones and personal digital assistants (PDA). Due to the mobility of mobile terminals, it is necessary to Frequently change network attachment points such as base stations or wireless network access points to enhance the application performance of wireless networks.

Currently, the dual radio interface scheme has been adopted as a promising solution in academic and industrial applications to support fast handover processing in homogeneous wireless networks or heterogeneous wireless networks. The direct purpose of the dual-radio solution is to establish two connection links connecting the mobile terminal and the network so that when handover occurs, they can be connected first and then disconnected to ensure that data is not lost. However, such continuous multiple connection links will result in definite energy consumption, which is also a serious concern in practical mobile terminal products. This problem has also attracted the attention of mobile terminal manufacturers and designers, but due to the unsatisfactory battery performance of mobile terminals and the research on high-efficiency power supply solutions for mobile terminals is progressing slowly. Therefore, the current dual radio frequency solution needs to be further improved in terms of energy saving.

Contents of the invention

The technical problem to be solved by the present invention is to provide a wireless network in view of the problem that the prior art does not consider energy saving but only considers the QOS factor in fast handover as the highest priority factor, which leads to the inability to reduce the energy consumption of the mobile terminal. An energy-efficient dual-radio interface scheduling method for fast handover.

The technical solution adopted by the present invention to solve the technical problem is: to construct an energy-saving dual radio frequency interface scheduling method for fast switching, the method comprising:

Calculate and collect the measurement data of multiple smart triggers according to the measurement values of different layers of the wireless network link accessed by the mobile terminal, and obtain the scanning decision value according to the multi-condition decision normalization algorithm;

When the smart trigger is in a normal state, the mobile terminal executes the smart trigger decision scan according to the scan decision value, otherwise, performs periodic scan.

In the method of the present invention, the wireless network includes a homogeneous wireless network or a heterogeneous wireless network.

In the method of the present invention, the intelligent trigger is an index indicating handover.

In the method of the present invention, the linear system formula of described multi-condition judgment normalization algorithm is:

$\mathrm{<span\; class="notranslate">\; ScanTriggerDecision</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}$

Among them, ScanTriggerDecision is a scan decision value, w _i is a weight value, and f _i is a smart trigger value.

In the method of the present invention, the non-linear system formula of described multi-condition judgment normalization algorithm is:

$\mathrm{<span\; class="notranslate">\; ScanTriggerDecision</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}$

Among them, ScanTriggerDecision is a scan decision value, w _i is a weight value, and f _i is a smart trigger value.

In the method of the present invention, at least two smart triggers are used for the plurality of smart triggers.

In the method of the present invention, the mobile terminal includes two radio frequency interfaces, one radio frequency interface is used for conventional operations such as communication, and the other radio frequency interface is used for active scanning and connection establishment. After switching, the two radio frequency interfaces Interchange operation.

In the method of the present invention, the scanning period of the periodic scanning is adjusted according to the following method:

When the switching frequency indication is greater than the switching frequency threshold value, shorten the scanning cycle of the periodic scanning by a step size α; otherwise, extend the scanning cycle of the periodic scanning by a step size β.

In the method of the present invention, the step sizes α and β can range from but not limited to 20 milliseconds to 1 second in an 802.11-based system.

In the method of the present invention, the switching frequency indication is determined according to the number of switching times per unit time when the sampling window is determined, and the calculation formula is:

$\mathrm{<span\; class="notranslate">\; HandoffFreqIndicator</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; *</span><span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; handoff</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; sample</span>}}}<span\; class="notranslate">\; )</span>$

Among them, HandoffFreqIndicator is a handover frequency indicator, f is an adjustment factor, n _handoff is the number of handoff occurrences, and t _sample is a sampling time window.

The beneficial effects of the present invention are: through the dual radio frequency interface scheduling method for fast switching provided by the present invention, dual radio frequency interfaces are activated and deactivated in turn to perform active scanning, and the scanning is made more accurate by using an intelligent trigger, and at the same time Unnecessary scanning and connection operations are reduced through adaptive scheduling, thereby reducing the energy consumption of the mobile terminal without reducing the handover performance, and the online time of the mobile terminal will also be greatly extended.

Description of drawings

Fig. 1 is a flowchart of a dual radio interface scheduling method for fast handover according to a preferred embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Fig. 1 is a flowchart of a dual radio interface scheduling method for fast handover according to a preferred embodiment of the present invention. As shown in FIG. 1, the method flow 100 starts at step 102. With the rapid development of wireless communication technology, a large number of mobile terminals with dual radio frequency interfaces appear in the application of homogeneous wireless networks and heterogeneous wireless networks. Such as mobile phones, personal digital assistants (PDAs) and notebook computers. In order to improve communication efficiency and performance, the mobile terminal has two radio frequency interfaces connected to the wireless network, which can quickly switch between different communication links or different networks.

是链路层传输速率触发扫描的智能触发器，表征一定时间窗口内的传输速率变化率，其中w_i是权重，r_i是传输速率。In step 104, the mobile terminal calculates and collects measurement data of a plurality of smart triggers according to measurement values of different wireless communication links. In a preferred embodiment of the present invention, the smart triggers f ₁ , f ₂ ,...f _i include signal-to-interference ratio (Signal-to-Interference), transmission rate slope (Transmission Rate Slope) and packet loss rate (Packet Lost Ratio) and the like, the smart trigger is an index indicating switching, and in a preferred embodiment of the present invention at least two smart triggers are used, specifically to different smart triggers, for example,

It is an intelligent trigger for link layer transmission rate trigger scanning, which represents the rate of change of transmission rate within a certain time window, where w _i is the weight and _ri is the transmission rate.

其中，ScanTriggerDecision是扫描决定值，w_i是权重值，f_i是智能触发器值。即通过赋予智能触发器权重来调节不同层智能触发器的影响；在对智能触发器更加敏感的非线性系统中，所述多条件判决归一算法的公式是：

其中，ScanTriggerDecision是扫描决定值，w_i是权重值，f_i是智能触发器值。根据具体应用的需要，在物理层、网络层或应用层都可以设置不同的智能触发器。In step 106, a scan decision value is obtained through normalized fusion of multiple smart triggers. The normalization fusion is to adopt the multi-condition judgment normalization algorithm. For a linear system, the formula of the multi-condition judgment normalization algorithm is:

Among them, ScanTriggerDecision is a scan decision value, w _i is a weight value, and f _i is a smart trigger value. That is, the influence of different layers of smart triggers is adjusted by assigning weights to smart triggers; in a non-linear system that is more sensitive to smart triggers, the formula of the multi-condition judgment normalization algorithm is:

Among them, ScanTriggerDecision is a scan decision value, w _i is a weight value, and f _i is a smart trigger value. According to the needs of specific applications, different smart triggers can be set at the physical layer, network layer or application layer.

In step 108, it is judged whether to adopt the trigger judgment scan, if the state of the smart trigger is normal, that is, when it can work normally, the trigger judgment scan is adopted, and step 110 is continued; When the smart trigger of the link measurement fails to work normally, it performs periodic scanning, that is, executes step 112 .

In step 110, since trigger decision scanning is adopted, the corresponding scanning scheduling control signal is sent to the network interface card of the dual radio frequency interface of the mobile terminal according to the scanning decision value calculated by the multi-condition decision normalization algorithm, Active scanning is performed by activating and deactivating the dual radio frequency interfaces in turn, and then ends at step 122 .

In step 112, periodic scanning is used, the scanning period is adjusted by an adaptive algorithm, which means, in principle, that the number of scans is increased when the switching frequency indicates that the connection is about to be made, or conversely, when the switching frequency indicates that the connection is about to be disconnected The number of scans is reduced.

In step 114, it is judged whether the handoff frequency indicator (HandoffFreqIndicator) is greater than the handoff frequency threshold (FrqThreshold), if the handoff frequency indicator is greater than the handoff frequency threshold, execute step 116, otherwise execute step 118.

In step 116, the handoff frequency indicator is greater than the handoff frequency threshold, that is, HandoffFreqIndicator>FrqThreshold

Then ScanIntervali=ScanIntervali-α wherein, ScanIntervali is the scanning interval, α is the step size, that is, shortening the scanning cycle of the periodic scanning, and the shortened step size is α.

In step 118, the handoff frequency indication is not greater than the handoff frequency threshold value, that is, HandoffFreqIndicator≤FrqThreshold

Then ScanIntervali=Min((ScanIntervali+β), ScanIntervalThreshold) wherein, ScanIntervali is the scanning interval, β is the step size, that is, the scanning period of the periodic scanning is extended, and the extended step size is β. α and β are determined according to actual scenarios such as mobility, distribution density of APs (base stations or access points), types of mobile terminals (such as smartphones or laptops), and types and quantities of applications running on the terminals. For uninterrupted mobile scenes, the range of empirical values α and β can be 20ms to 50ms; for occasional mobile nomadic scenes, α and β can be relaxed to 1s, for example, in 802.11-based systems, it can be 20ms to 50ms. 1 second. FrqThreshold and ScanIntervalThreshold are also affected by the moving speed of mobile terminals, the distribution density of APs (base stations or access points) and the frequency of adaptive actions, usually several times per second in scenarios.

In step 120, according to the adaptive algorithm of step 116 or step 118, the scanning cycle of periodic scanning is adjusted, and the scanning scheduling control signal is sent to the network interface card of the dual radio frequency interface of the mobile terminal, and activation and deactivation are adopted in turn Dual radio interfaces to perform active scanning.

The method flow 100 of the preferred embodiment of the present invention ends at step 122 . Since the dual radio scheduling method of the present invention uses alternate activation and deactivation of dual radio interfaces to perform active scanning, the simultaneous scanning decision involves two factors, the measurement of the radio link metric as a smart trigger and the previous handover as a scheduler knowledge of history. Smart triggers and scheduler algorithms are used to handle the complexity when handovers occur in order to control the radio interface accordingly. The ratio can effectively reduce the scanning decision error in the cluttered wireless communication environment. Since the method of the present invention reduces unnecessary scanning and connection operations through adaptive scheduling and makes scanning more accurate by using an intelligent trigger, the energy consumption of the mobile terminal is reduced without reducing the handover performance.

The method of the present invention is applied on a mobile terminal with two radio frequency interfaces, one radio frequency interface is used for conventional operations such as communication, and the other radio frequency interface is used for active scanning and connection, and the purpose is to achieve fast switching (i.e. disconnection after connection) ), after switching, the two radio interfaces operate interchangeably. The dual radio frequency interface includes two homogeneous interfaces of the same wireless network or heterogeneous interfaces belonging to different wireless networks. Any application that is sensitive to disconnection or switching between networks, such as streaming video applications and VOIP applications, will benefit by developing fast switching. By adopting the method of the present invention, the above-mentioned energy consumption of the mobile terminal will be reduced and at the same time, the online time of the mobile terminal will be greatly extended, which is also one of the most concerned factors for mobile terminal manufacturers.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (8)

1. A dual radio interface scheduling method for fast switching, characterized in that the method comprises: Calculate and collect the measurement data of multiple smart triggers according to the measurement values of different layers of the mobile terminal accessing the wireless network link, and obtain the scanning decision value according to the multi-condition judgment normalization algorithm; When the smart trigger is in a normal state, the mobile terminal executes the smart trigger decision scan according to the scan decision value, otherwise, performs periodic scan. 2. The dual radio frequency interface scheduling method for fast handover according to claim 1, wherein the wireless network comprises a homogeneous wireless network or a heterogeneous wireless network. 3. The dual radio frequency interface scheduling method for fast handover according to claim 1, characterized in that: the smart trigger is an index indicating handover. 4. The dual radio frequency interface scheduling method for fast switching according to claim 1, characterized in that: the linear system formula of the multi-condition judgment normalization algorithm is: $\mathrm{<span\; class="notranslate">\; ScanTriggerDecision</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}$ The nonlinear system formula is: $\mathrm{<span\; class="notranslate">\; ScanTriggerDecision</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}$ Among them, ScanTriggerDecision is a scan decision value, w _i is a weight value, and f _i is a smart trigger value. 5. The dual radio frequency interface scheduling method for fast switching according to claim 1, wherein at least two smart triggers are used for the plurality of smart triggers. 6. The dual radio frequency interface scheduling method for fast switching according to claim 1, characterized in that: the mobile terminal includes two radio frequency interfaces, one radio frequency interface is used for conventional operations such as communication, and the other radio frequency interface is used for For active scanning and connection establishment, after switching, the two radio interfaces operate interchangeably. 7. The dual radio frequency interface scheduling method for fast switching according to claim 1, characterized in that: the scanning period of the periodic scanning is adjusted according to the following method: When the switching frequency indication is greater than the switching frequency threshold value, shorten the scanning cycle of the periodic scanning by a step size α; otherwise, extend the scanning cycle of the periodic scanning by a step size β. 8. The dual radio frequency interface scheduling method for fast handover according to claim 7, characterized in that: the handover frequency indication is determined according to the number of handovers that occur per unit time when the sampling window is determined, and the calculated formula for: $\mathrm{<span\; class="notranslate">\; HandoffFreqIndicator</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; *</span><span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; handoff</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; sample</span>}}}<span\; class="notranslate">\; )</span>$ Among them, HandoffFreqIndicator is a handover frequency indicator, f is an adjustment factor, n _handoff is the number of handoff occurrences, and t _sample is a sampling time window.