CN1698389A - Method and system for avoiding power outages at the base station in cellular system using variable rate transmission - Google Patents

Abstract

The present invention discloses a method and system for discarding the least amount of data in case a power outage is expected to occur in some timeslot during a future frame. The present invention discloses using Base Station (BS) information on the power transmitted during the last frame, along with information on the total amount of data, and the priority assigned thereto, that the BS has to transmit during upcoming frames, to make decisions on the type and quantity of data that should be removed to avoid severe power outage in the upcoming frames.

Description

Method and system for avoiding base station power interruption in a mobile phone system using variable rate transmission

technical field

The present invention relates to the field of wireless communication. In particular, the present invention relates to third generation mobile phone systems utilizing variable rate transmission in downlink transmission.

Background technique

The third generation (3G) mobile phone system will use radio network controller (RNC) and base station (BS). Among them, traffic (downlink transmission) transmitted to users via the core network is routed to a base station (BS) that can provide the best service for a given user by using a radio network controller (RNC). For a given user, the data transmitted to the base station (BS) via the radio network controller (RNC) will be divided into several transmission channels (DCH), and each transmission channel (DCH) will have a coding type (coding type), rate (rate), interleaving (interleaving) features. The base station (BS) periodically collects the transmission block data of the radio network controller (RNC), performs appropriate coding and interleaving on each transmission channel (DCH), multi-tasks the data of different transmission channels (DCH), and The data is transmitted via the appropriate physical channel (DPCH). A physical channel (DPCH) is defined using a spreading code and, in the case of discontinuous transmission (time division duplex (TDD)), time slots.

For a given user, the power of the transmitted signal on a given physical channel (DPCH) depends on several factors, such as: the path loss between the user and the base station, the interference level perceived by the user Accurate and satisfactory signal-to-interference ratio (SIR) for transmission. For a given user, the required signal-to-interference ratio (SIR) for a given physical channel (DPCH) may depend on the amount of data to be transmitted over the different transport channels (DCH) during a specific time period (frame). This amount of data may be referred to as a Transport Format Combination (TFC).

When the signal-to-interference ratio (SIR) changes upward or downward, the user will use the uplink transmission channel to periodically request the base station (BS) to adjust its power downward or upward. The base station (BS) can decide whether to meet the user's requirements. In a given time slot, the total power to transmit all physical channels (DPCH) cannot exceed a certain threshold. If the base station (BS) finds that a certain situation may violate the specific threshold, the base station (BS) needs to reduce the power of each physical channel (DPCH) (respectively by the same relative amount), so as to avoid exceeding the specific threshold. This situation is called a power outage.

Congestion is a general term for the following conditions, that is, the base station (BS) cannot satisfactorily transmit all the users or user equipment (UE) transmitted to the connecting base station (BS) via the radio network controller (RNC). )The data. This is due to insufficient hardware resources, processing power, or transmission power. In order to provide a mechanism by which the base station (BS) can schedule priority among transport channels (DCH) in the case of congestion, the radio network controller (RNC) will target each transport channel (DCH) Assign priority, namely: Frame Handling Priority (FHP). The frame processing priority (FHP) is assigned by the radio network controller (RNC) and transmitted to the base station (BS), so that most of the important data can pass through successfully in the congestion (congestion) situation.

However, this method does not indicate how low priority data should be discarded to ensure that no severe power outage occurs. In view of this, the present invention proposes a method and system, which simultaneously considers the power requirement and the frame processing priority (FHP) of transmitting data, so as to discard the optimal amount of data in the case of congestion.

Contents of the invention

The object of the present invention is to provide a method and system for avoiding power outage of base stations in mobile phone systems using variable rate transmission. In the event of congestion, the present invention can consider the power requirements of the data and the frame processing priority (FHP), so as to discard the optimal amount of data.

A method for avoiding power interruption of a base station in a mobile phone system utilizing variable rate transmission according to one aspect of the present invention, the method includes the following steps: A) calculating at least one future frame, each time slot B) identifying time slots with a transmission power requirement greater than a predetermined threshold; C) selecting the time slot with the highest transmission power requirement; D) identifying the transmission channel of the selected time slot; E) ordering the identified transport channel firstly by increasing the frame processing priority and secondly by reducing the associated transmit power; F) applying a tag which temporarily indicates: the data in a transport channel to which the tag is applied will be discarded, and recalculate the transmission power demand forecast for the selected time slot of each identified transport channel in the order of the sorted transport channels until the transmission power demand forecast is equal to or less than a predetermined threshold; G ) temporarily removes the tag previously applied to each transport channel in the reverse order of the sorted transport channel, and recalculates the transmission power requirement forecast after each successive tag removal, thereby determining whether any tag removal will causing the transmission power demand forecast to exceed the predetermined threshold; and H) suppressing data transmission for any transport channel whose tag removal would cause the transmission power demand forecast to exceed the predetermined threshold.

According to another aspect of the present invention, a system for avoiding power interruption in a mobile phone system using variable rate transmission, the system includes: A) a radio network controller, wherein data for at least one user is transmitted to A base station; B) wherein, the data transmitted to the base station by the radio network controller is assigned a frame processing priority, and is separated into transmission channels mapped to physical channels, and transmitted to the at least one using or; and C) the base station is used to identify at least one future frame time slot with a transmission power demand prediction greater than a predetermined threshold value, and according to the predetermined threshold value, optimize the time slot of each identified time slot The transmit power demand forecast.

In order to clearly understand the purpose, features and advantages of the present invention, preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Description of drawings

FIG. 1 is a flowchart of a method for avoiding power outage of a base station according to a preferred embodiment of the present invention.

FIG. 2 is a block diagram of a system for discarding an optimal amount of data in a congestion situation according to a preferred embodiment of the present invention.

Detailed ways

The present invention uses the transmission power information of the base station (BS) during the last frame period, and the total amount of data that the base station (BS) must transmit during the subsequent frame period, so as to determine the type and quantity of data that should be discarded, thereby avoiding Severe power outage for subsequent frames. This allows the base station (BS) to decide not only which data should be discarded, but also how much should be discarded. In addition, during the decision process, the base station (BS) also considers the frame processing priority (FHP) of the data. In the case of discarding data, the present invention discards data according to priority and minimizes the amount of data that should be discarded, thereby avoiding power outage.

As mentioned earlier, for a specific user, the data transmitted to the base station (BS) via the radio network controller (RNC) is divided into several transmission channels (DCH). Data transmitted over one set of transport channels (DCH) is multiplexed onto a coded hybrid transport channel (CCTrCH). The coded hybrid transport channel (CCTrCH) is transmitted on a specific number of physical channels (DPCHs) set by the coded hybrid transport channel (CCTrCH). In a given frame, the number of physical channels (DPCHs) used by the Coded Hybrid Transport Channel (CCTrCH) depends on the amount of data that needs to be transmitted during that frame.

When the data of the transmission channel (DCH) is discarded, for a given user, the number of physical channels (DPCH) required to support data transmission will also be reduced. If the selected time slot no longer needs part of the physical channel (DPCH), the transmission power requirement (P _{s ; n} ) of the selected time slot will also be reduced. In view of this, the present invention must evaluate what effect different combinations of transmission channels (DCHs) for de-tagging data will have on the transmission power requirement (P _s;n ) of a selected time slot. In addition, the transmission power requirement (P _{s; n} ) of the selected time slot can also be recalculated and compared with a predetermined threshold (P _thr ) representing the maximum allowable transmission power, assuming that the data of each transmission channel (DCH) alternates Both can be transferred and discarded. This enables the base station (BS) to select the combination of transmit/discard transmission channels (DCH) for the selected time slot, thereby obtaining the optimal amount of data that should be discarded and ensuring the transmission power requirement (P _{s; n} ) for the selected time slot A predetermined threshold (P _thr ) will not be exceeded.

Before the base station (BS) can process (that is: code (code), interleave (interleave), and multiplex (multiplex)) and transmit the data of a specific transmission channel (DCH), the base station (BS) must receive in advance data to the Radio Network Controller (RNC), and buffer the data for transmission during the next n frames, where n is the number of frames interleaved on the transport channel (DCH). The corresponding period is usually called transmission time interval (TTI), which will vary with the transmission channel (DCH) according to the characteristics of the data carried. In this way, data for a given transport channel (DCH) can be buffered and transmitted every n frames.

In each frame, the base station can predict the transmission of each time slot in the next frame or the next few frames (if necessary) based on the data to be transmitted on different transmission channels (DCH) and the currently used transmission power Power requirement (P _{s; n} ). If the base station (BS) determines according to the comparison of the transmission power requirement (P _{s; n} ) and the predetermined threshold (P _thr ): a specific time slot of the next frame has a significant risk of power outage, then this time slot Will be selected for further evaluation. That is to say, the base station (BS) will observe the buffered data scheduled for transmission in the next (next few) frames, and discard part of the data of the transmission channel (DCH), so that the affected time slots and frame The transmit power requirement (P _{s; n} ) will not exceed a predetermined threshold (P _thr ). This predetermined threshold (P _thr ) can be adjusted to make the method less aggressive.

In order to calculate the transmit power requirement (P _s;n ) for future frames, we must assume or know the following information:

For future frames, the transmission power of each physical channel (DPCH) of each coded hybrid transport channel (CCTrCH).

During the future frame, the transport format combination (TFC) of each coded hybrid transport channel (CCTrCH), because the transport format combination (TFC) can determine the number of physical channels (DPCH) used.

对于在未来讯框期间不具有数据的编码混合传输信道(CCTrCH)而言，是否预期传送特别丛讯。

Whether transmission of ad hoc bursts is expected for a Coded Hybrid Transport Channel (CCTrCH) with no data during future frames.

However, the transmission power of each used physical channel (DPCH) cannot be known precisely, even for the next frame. Therefore, the method of the present invention will use the first layer control, that is: the latest transmission power reported by the first layer (Layer1) of the base station (BS), so as to calculate the transmission power requirement (P _{s; n} )predict. The latest transmission power reported by the first layer of control is preferably the transmission power used in the current frame, or the previous frame (if the information cannot be obtained in time).

For example, the transmit power requirement (P _s;n ) for time slot s can be calculated according to the following equation:

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; ;</span>\mathrm{<span\; class="notranslate">\; no</span>}}{<span\; class="notranslate">\; =</span>}_{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; NK</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; ;</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

where g(k, s; n) is the hypothetical transmission power of the physical channel (DPCH) used by the coded hybrid transport channel (CCTrCH) k in time slot s during frame n; N _k is the number of users; c _k (n) is the expected transport format combination (TFC) of coded hybrid transport channel (CCTrCH) _k during frame n; transmits a special burst, implying that the transport format combination (TFC) has no data); and u _k (s, c, d) is the number of physical channels (DPCHs) used by the coded hybrid transport channel (CCTrCH) in time slot s, if Transmit Transport Format Combination (TFC) c or transmit ad hoc burst (wherein, d=1 means that ad hoc burst is expected to be transmitted).

Once the transmission power requirement (P _{s; n} ) of each time slot of the next n future frames is calculated, the transmission power requirement (P _{s; n} ) will be compared with a predetermined threshold (P _thr ). If calculated by the method of the present invention: the transmission power requirement (P _{s; n} ) of at least one time slot or frame exceeds a predetermined threshold (P _thr ), then this time slot will be further evaluated to discard data. If there is more than one time slot with the transmission power requirement (P _{s; n} ) greater than the predetermined threshold value (P _thr ), the time slot with the highest transmission power requirement (P _{s; n} ) will be selected first and further evaluated to Ditch the data. Then, the remaining time slots are evaluated in order of decreasing transmission power requirements (P _s;n ). In contrast, if there is no time slot with transmission power requirement (P _s;n ) greater than the predetermined threshold (P _thr ), the method of the present invention does not need to perform any processing and all data can be transmitted.

The transport channel (DCH) of the time slot selected for the corresponding data discarding consideration may be referred to as the "associated" transport channel (DCH). In addition, these relevant transport channels (DCH) can be defined according to the considerations of the present invention as follows:

这个(这些)传输信道(DCH)在下一个讯框期间，具有欲传送的数据。

The transport channel(s) (DCH) have data to transmit during the next frame.

This (these) transport channel (DCH) is the coded hybrid transport channel (CCTrCH) "involved" in the problem slot, i.e. the slot for which the transmit power requirement (P _s;n ) is greater than a predetermined threshold (P _thr ) part. If this time slot has at least one physical channel (DPCH) mirroring this (this) transport channel (DCH), as previously described, then this coded hybrid transport channel (CCTrCH) will be called: "involved" in the problem groove.

These associated transport channels (DCH) are ordered according to predetermined criteria. Preferably, the ordering of the transport channels (DCH) is firstly based on the frame processing priority (FHP) of the transport channel (DCH) (lower frame processing priority (FHP) is preferred), and secondly based on the transport channel ( DCH) relative transmission power (high power priority). The relative transmit power is defined as the transmit power of the coded hybrid transport channel (CCTrCH) to which the transport channel (DCH) belongs. In this way, within a certain frame processing priority (FHP), the method of the invention can preferentially affect the transport channel (DCH) constituting the coded hybrid transport channel (CCTrCH) with high power requirements. These coded hybrid transport channels (CCTrCHs) may belong to users with high path loss due to non-ideal location relative to the serving base station (BS).

Subsequently, the method of the present invention can place a "tag" on the first transmission channel (DCH) in the list and recalculate the transmission power requirement (P _{s; n} ) of the selected problem slot and frame, as before described, but it must be assumed that this tag transport channel (DCH) will not transmit any data. If the transmission power requirement (P _{s; n} ) is still greater than the predetermined critical value (P _thr ), the method of the present invention will proceed to the next transmission channel (DCH) in the list, and continue to perform the above steps until the transmission power requirement (P _{s; n} ) is less than a predetermined threshold (P _thr ), or until there are no other transport channels (DCH) in the list.

So far, although the transmission power requirement (P _{s; n} ) may be smaller than the predetermined threshold (P _thr ), the method of the present invention will continue to be executed, because some tags of the tag transmission channel (DCH) may be removed. That is, a specific transport channel (DCH) may be restored without the transmit power demand (P _s;n ) rising above the predetermined threshold (P _thr ) (or not at all). These transport channels (DCH) should be omitted. Therefore, the method of the present invention will use the reverse order of the transmission channel (DCH) list to recalculate the transmission power requirement (P _{s; n} ), thereby temporarily removing the label of each transmission channel (DCH) and checking the transmission power Whether the demand (P _{s; n} ) increases and rises above the predetermined threshold (P _thr ). If removal of a specific transport channel (DCH) tag does not cause the transmit power requirement (P _s;n ) to rise above a predetermined threshold (P _thr ), then the transport channel (DCH) tag is removed. Conversely, if the removal of the transport channel (DCH) label can bring the transmission power requirement (P _{s; n} ) back above the predetermined threshold (P _thr ), the transport channel (DCH) will be re-labeled and will not The data will be transmitted.

After the abandonment procedure of the first (ie: worst) problem time slot is completed, the method of the present invention will restart if necessary. In this case, the transmission power requirements (P _{s; n} ) of all other time slots will be recalculated, and the method of the present invention will also start from the new "worst" problem time slot, if there are also For other time slots (excluding time slots that have already executed the discarding program). The main reason for recalculating the transmission power requirements (P _{s; n} ) of other time slots is that the transmission power requirements (P _{s; n} ) of other time slots may also discard data in some transmission channels (DCH) to release other time slots The congestion (congestion) situation is followed by a reduction. This can indeed happen if the coded hybrid transport channel (CCTrCH) uses a physical channel (DPCH) with different time slots.

After all problem slots have been processed, the method of the present invention can end. Then, the transport data can be passed to the layer 1 control, and these tag transport channels (DCH) will not transmit any data. Theoretically, reducing the transport format of a partial transport channel (DCH) to a transport format combination (TFC) with no data may generate errors in partial frames. After carrying out this discard procedure, if the inventive method detects that this situation is imminent, the inventive method reduces the transport format of these simultaneously transmitted transport channels (DCH) until the correct transport format combination (TFC) occurs. If this is not possible (for example, because data on other transport channels (DCH) have already been transmitted), the method of the present invention returns the transport format provided by the radio network controller (RNC) to the base station (BS) .

FIG. 1 is a diagram showing the execution steps of the method of the present invention, which are numbered 10 . Through the method of the present invention, only the transport channel (DCH) data to which the user of the assigned physical channel (DPCH) belongs during the selected time slot is considered discarded.

The method of the present invention starts at step 12 to identify problem time slots, wherein the data of the problem time slots will be considered and discarded. In order to identify problem slots, the present invention must calculate the transmission power requirement (P _s;n ) forecast for each slot s in the next n frames. Then, the time slots whose transmission power requirement (P _{s; n} ) is greater than the power threshold (P _thr ) can be identified as problematic time slots.

The power threshold (P _thr ) is an adjustable predetermined value based on the maximum allowable power of the base station (BS). The power threshold (P _thr ) can be any value, but it is preferably an integer multiple of the maximum allowable power of the base station (BS), for example: 1 to 5 times. The power threshold (P _thr ) is used to control the aggressiveness of data discarding. In particular, when the power threshold (P _thr ) is high, the degree of discarding data by the method of the present invention will be more conservative. That is, a higher power threshold (P _thr ) will identify fewer problem slots, thereby reducing the number of transport channels (DCHs) considered for data discarding.

In step 14, the present invention will decide whether step 12, in fact, identifies any problem slots. If step 12 does not identify any problem slots, the method of the invention will end in step 15 and can start anew if desired. On the contrary, if step 12 does identify a problem slot, the method of the present invention will proceed to step 16, and select the problem slot with the largest transmission power requirement (P _s;n ). In step 18, the method of the present invention identifies the associated transport channel (DCH). As mentioned earlier, for a given user, the data transmitted by the Radio Network Controller (RNC) to the Base Station (BS) will be segmented into a set of Transport Channels (DCH), which is a mix of multiplexed to coded transmissions channel (CCTrCH), and mapped to a physical channel (DPCH) for transmission to users. In the presently selected problem slot, the transport channel (DCH) utilizing the physical channel (DPCH) may be referred to as the "associated" transport channel (DCH).

In step 20, the associated transport channels (DCHs) are sorted in order of increasing frame processing priority and decreasing associated transmission power. The relevant transmission power of a specific transport channel (DCH) is the transmission power of the coded hybrid transport channel (CCTrCH) to which this transport channel (DCH) belongs. In step 22, Dmax is defined as the number of associated transport channels (DCH). In step 24, the method of the present invention determines whether Dmax is equal to zero. If Dmax is equal to 0, it means that there is no relevant transmission channel (DCH) in this time slot, and the method of the present invention will return to step 16, and select the time slot with the second highest transmission power requirement (P _s;n ). If Dmax is not equal to 0, the method of the present invention will proceed to step 26, wherein, D is defined as considering a specific DCH outside the DCH group, and is set to 1. This ensures that the first DCH in the list is considered first, so that the DCH with the lowest priority and highest transmission power is evaluated first.

In step 28, the Dth (ie first, second, third, etc.) associated transport channel (DCH) is tagged to discard data. That is to say, if D is equal to 1, the first associated transport channel (DCH) will perform tagging to discard data. Then, in step 30, the transmission power requirement (P _s;n ) of the selected time slot is recalculated, assuming that data on the Dth associated transport channel (DCH) will not be transmitted. Next, in step 32, the method of the present invention determines whether the transmission power requirement (P _{s; n} ) is smaller than the power threshold (P _thr ). If the transmission power requirement (P _{s; n} ) is less than the power threshold (P _thr ), the method of the present invention will proceed to step 36, wherein the tag of the D-th relevant transmission channel (DCH) will be removed, so as to make this The inventive method makes it possible to determine whether this transport channel (DCH) has to be discarded. If the transmission power requirement (P _{s; n} ) is not less than the power threshold (P _thr ), the method of the present invention determines whether D is equal to Dmax in step 34, that is, whether all relevant transmission channels (DCH) have been considered. If D is not equal to Dmax, it means that all relevant transport channels (DCH) have not been fully considered, and the method of the present invention will proceed to step 35 . In step 35, D is incremented by 1 to tag and consider the next associated transport channel (DCH) to discard data, as previously described.

Once steps 28 to 3 have been completed, for each associated transport channel (DCH), the data necessary to reduce the transmit power requirement (P _s;n ) below the power threshold (P _thr ) has been tagged and be discarded. However, tagging and throwing away too much data can also pose risks. Therefore, the method of the present invention also continuously evaluates the possible effect of discarding tags in different DCH combinations. This can ensure that the present invention can discard the optimal amount of data, so that most of the data will not be discarded unnecessarily, and also can reduce the transmission power requirement (P _s;n ) of the selected time slot.

As mentioned earlier, the tag of the D-th associated transport channel (DCH) is removed in step 36 . Then, in step 38, the present invention calculates a temporal forecast of the transmission power requirement (P'_s;n ). The calculation of the transmit power requirement (P'_{s; n} ) will also take into account the current state (ie whether it has a tag or not) of the associated transport channels (DCH).

In step 40, the method of the present invention evaluates the transmission power requirement (P _{'s; n} ) according to the transmission power requirement (P s; n ) and the power threshold ₍ P _thr ). In particular, in step 40, the method of the present invention determines whether the transmission power requirement (P'_{s; n} ) is greater than the transmission power requirement (P _{s; n} ) and the power threshold (P _thr ). If the transmission power requirement (P'_{s; n} ) is greater than the transmission power requirement (P _{s; n} ) and the power threshold (P _thr ) at the same time, it means: the transmission power requirement (P _{s; n} ) of the selected time slot may not be able to Data using the Dth associated transport channel (DCH) is substantially reduced. Therefore, if the label removal of the relevant transmission channel (DCH) will cause the transmission power requirement (P'_{s; n} ) to be greater than the transmission power requirement (P _{s; n} ) and the power threshold (P _thr ), then the relevant transmission channel ( DCH) just needs to carry out labeling again in step 42, thereby discards the data of this relevant transmission channel (DCH). Relatively, if the method of the present invention determines in step 40 that: the transmission power requirement (P'_{s; n} ) is not greater than the transmission power requirement (P _{s; n} ) and the power threshold (P _thr ), it means: the time slot is selected The transmission power requirement (P _{s; n} ) of can be sufficiently reduced, and the data of the D-th associated transport channel (DCH) can be transmitted. In this case, the D-th associated transport channel (DCH) will remain untagged, and the method of the present invention will proceed to step 41, wherein the transmit power requirement (P _{s; n} ) will be set equal to the transmit power requirement (P's _{; n} ).

Next, the method of the present invention will proceed to step 44 no matter whether the D-th relevant transport channel (DCH) is relabeled or not. In step 44, the method of the present invention will determine whether the Dth associated transport channel (DCH) is the first associated transport channel (DCH), thereby ensuring that all associated transport channels (DCHs) previously considered to receive tags will use the opposite direction, Likewise reconsider and remove the label. This enables discarding the appropriate DCH combination to optimize the transmission power requirement (P _{s; n} ) according to the power threshold (P _thr ) (i.e., selecting the appropriate DCH combination To discard data, thereby discarding the minimum amount of data and ensuring that the transmission power requirement (P _{s; n} ) will not exceed the power threshold (P _thr )). It should be noted that the transmission power requirement (P _{s; n} ) is optimized according to the power threshold value (P _thr ), and the method of the present invention can also make the transmission power requirement (P _{s; n} ) as close as possible to the power threshold value (P _thr ), and of course the power threshold (P _thr ) will not be exceeded.

If the Dth associated transport channel (DCH) is the first associated transport channel (DCH) (that is, D is equal to 1), the method of the present invention will proceed to step 46 . If not, the method of the present invention will continue to step 45, wherein D will be incremented by 1, so as to consider removing the tag of the next relevant transport channel (DCH).

Once all appropriate relevant transport channels (DCH) have been considered (step 28 to step 35) and reconsidered (step 36 to step 45) to discard data, the method of the present invention will determine whether there are other problems in step 46 slot (identified by step 12). If there are other problem slots, the method of the present invention will proceed to step 48 to recalculate the transmission power requirement (P _s;n ). Once the transmission power requirements (P _{s; n} ) of all remaining problem slots have been recalculated, step 16 will select the time slot that now has the largest transmission power requirement (P _{s; n} ), and the method of the present invention will also be performed by This continues, as previously described. On the contrary, if there are no other problem slots, the method of the present invention will end in step 50 and no tagged data will be transmitted.

In order to provide an example of implementing the method of the invention, it is assumed that there are a total of three relevant transport channels (DCH) D1, D2, D3, wherein transport channel (DCH) D3 has the highest frame processing priority (FHP), and transport channel ( DCH) D1 and D2 have the same frame processing priority (FHP). In addition, it is assumed that the power threshold (P _thr ) is 1.0W, and the individual relevant transmission powers of the transmission channels (DCH) D1 , D2 , D3 are 0.1W, 0.1W, 1.1W.

Given the frame processing priorities (FHP) and associated transmit powers of these transport channels (DCHs), these transport channels (DCHs) can be ordered in step 20 as D1, D2, D3 (i.e. first increment frame processing priority (FHP), then decrements the associated transmit power). Therefore, D is equal to 1, 2, 3 for transport channels (DCH) D1, D2, D3, respectively. In addition, assume that the transmission power requirement (P _{s; n} ) of some or all channel data is:

D1+D2+D3: 1.3W

Only D2+D3: 1.2W

D3 only: 1.1W

D2 only: 0.1W

Only D1+D2: 0.2W

It can be known that the total transmission power requirement (P _s;n ) of the three transmission channels (DCH) is 1.3W, which is already greater than the power threshold (P _thr ) of 0.3W. Therefore, some data must be discarded to avoid exceeding the power threshold (P _thr ).

In this example, the low priority transport channels (DCH) D1 and D2 will be discarded first. Transport Channels (DCH) D1 and D2 are the first Transport Channels (DCHs) to be discarded first, since these associated Transport Channels (DCHs) are ordered first according to increasing Frame Handling Priority (FHP) and then according to decreasing The relative transmission power of , as described previously. However, dropping the tag transport channels (DCH) D1 and D2 is not enough to reduce the power threshold (P _thr ) to the power threshold (P _thr ). That is to say, discarding the data of the transmission channel (DCH) D1 and D2 will reduce the transmission power requirement (P _{s; n} ) from 1.3W to 1.1W, but the transmission power requirement (P _{s; n} ) will still be greater than 1.0 The power threshold (P _thr ) of W. Therefore, the transmission channel (DCH) D3 also needs to be discarded, so as to reduce the transmission power requirement (P _{s; n} ) below the power threshold (P _thr ). Unfortunately, however, dropping the tag transport channel (DCH) D3 will reduce the transmit power requirement (P _s;n ) to 0.0W, thereby interrupting any data transmission. This seems to be overkill, because the transmission power requirement (P _{s; n} ) is sufficient to meet the power threshold (P _thr ), although the frame processing priority (FHP) of the transport channel (DCH) D1 and D2 is indeed smaller than the frame processing priority (FHP) of the transport channel (DCH) D3.

This situation is taken into account during the demarking phase (steps 36 to 45) of the method of the present invention. In this case, the inventive method first removes the tag of the transport channel (DCH) D3. However, the label of the transmission channel (DCH) D3 will be reapplied in step 42, because, in step 40, the transmission power requirement (P'_{s; n} ) will be greater than the transmission power requirement (P _{s; n} ) and Threshold power (P _thr ) (ie: transmission power requirement (P'_{s; n} ) is equal to 1.1W, transmission power requirement (P _{s; n} ) is equal to 0.0W, and power threshold (P _thr ) is equal to 1.0W) . It should be noted that the transmission power requirement (P _s;n ) used in step 42 is the transmission power requirement (P _s;n ) affected by the previous tags in steps 26 to 35 . That is to say, in this example, the transmission channels (DCH) D1 , D2 , and D3 will all discard tags, and then the transmission power requirement (P _{s ; n} ) of 0.0 W is calculated in step 30 . Therefore, this transmission power requirement (P _{s; n} ) is compared with the transmission power requirement (P'_{s; n} ) in step 40 . In addition, if the transmission power requirement (P _{s; n} ) is set as the transmission power requirement (P'_{s; n} ) in step 41, then this transmission power requirement (P _{s; n} ) will also be used in step 40, if Step 44 of the method of the invention proceeds to step 45 and is thus continued. In general, the method of the present invention uses the latest calculated transmission power requirement (P _s;n ) whenever the transmission power requirement (P _s;n ) is compared with another parameter.

Returning to this example, once the label of the transport channel (DCH) D3 is reapplied in step 42, the method of the present invention will proceed to step 44, wherein the method of the present invention will determine whether D is equal to 1 (ie: currently whether the associated transport channel (DCH) of is considered as the first associated transport channel (DCH)). Since the transport channel (DCH) D3 is the third associated transport channel (DCH) and not the first associated transport channel (DCH), the method of the invention will continue because all previously considered transport channels (DCH) have not yet been fully reconsidered . Therefore, D will be decremented by 1 in step 45 , and then in step 36 the transport channel (DCH) D2 will be unmarked. In step 37, since transport channels (DCH) D3 and D3 have discard tags, and transport channel (DCH) D2 has been demarked, the transmit power requirement (P's _{; n} ) will become in step 38 0.1W (1.3W-1.1W-0.1W=0.1W). Therefore, the transmission power requirement (P'_{s; n} ) will not be greater than the transmission power requirement (P _{s; n} ) and the power threshold (P _thr ) at the same time. That is to say, the transmission power requirement (P'_{s; n} ) will be greater than the transmission power requirement (P _{s; n} ), but not greater than the power threshold (P _thr ) [that is, the transmission power requirement (P thr ) of 0.1W '_{s; n} ) will be compared with the transmission power requirement (P _{s; n} ) of 0.0W and the power threshold (P _thr ) of 1.0W]. Since the transmission power requirement (P'_{s; n} ) is still lower than the power threshold (P _thr ), even in the case of discarding the data of the transport channel (DCH) D2, the data of the transport channel (DCH) D2 can be permanently discarded. In addition, the processing method of the transport channel (DCH) D1 is also the same. Therefore, for the above example, the data of the transport channel (DCH) D3 will be discarded, while the data of the transport channels (DCH) D1 and D2 will be kept for transmission.

Now, please refer to FIG. 2, which shows a system to avoid power outage of the base station in the mobile phone system using variable rate transmission. The system includes a Radio Network Controller (RNC) 112 , a Base Station (BS) 114 , and a User Equipment (UE) 116 .

For a given user, the data transmitted to the base station (BS) 114 via the radio network controller (RNC) is segmented into several transmission channels (DCH). The base station (BS) 114 multiplexes the data of the transport channel (DCH) and maps it to the appropriate physical channel (DPCH). The base station (BS) 114 can predict the transmission power demand (P _{s; n} ) of each time slot in the next (next several) frames based on the data to be transmitted on different transmission channels (DCH) and the currently used transmission power predict. In addition, slots identified as problematic slots (ie, slots for which the transmission power requirement (P _{s; n} ) exceeds a power threshold (P _thr )) will be evaluated for data discarding.

DCH data for problem slots can be evaluated to identify optimal DCH combinations for data transmission/discarding. Once the transmission channels (DCHs) that discard the optimal amount of data can be identified, the data of these transmission channels (DCHs) can be transmitted without using the base station (BS) 114 . A base station (BS) 114 may send a signal to a radio network controller (RNC) 112 to indicate data not to be sent.

Although the present invention has been described in detail using preferred embodiments as above. However, those skilled in the art can make various possible changes and adjustments to the preferred embodiments of the present invention without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the following claims of the application.

Claims (21)

1. A method for avoiding power interruption of a base station in a mobile phone system utilizing variable rate transmission, the method comprising the steps of: A) calculating a transmission power requirement forecast for each time slot in at least one future frame; B) identifying time slots having a transmit power requirement greater than a predetermined threshold; and C) Optimizing the transmission power demand prediction for each identified time slot according to the predetermined threshold. 2. The method according to claim 1, wherein, according to the predetermined critical value, the step of optimizing the transmission power demand prediction of each identified time slot further comprises the following steps: A) identifying a frame processing priority and associated transmit power for a transmission channel having data to be transmitted on a physical channel of the identified time slot; and B) discarding data of the transport channel based firstly on the frame processing priority and secondly based on the relative transmit power of the transport channel. 3. The method according to claim 1, wherein, according to the predetermined critical value, the step of optimizing the transmission power requirement prediction of each identified time slot further comprises: A) identifying the frame processing priority and associated transmission power of a transmission channel having data to be transmitted on a physical channel of the identified time slot; B) applying a tag to each combination of the transport channels, which temporarily indicates that the data of the transport channel to which the tag is applied will be discarded; and C) Selecting to discard data in transport channels constituting a transport channel combination that optimizes the transmission power demand predictor for each identified time slot according to the predetermined threshold. 4. The method of claim 1, wherein the transmission power demand forecast for each time slot is calculated using information of a current frame. 5. The method of claim 4, wherein the transmission power requirement prediction for each time slot is calculated based on the transmission power used during the current frame. 6. The method of claim 1, wherein the predetermined threshold is based on a maximum allowable power of the base station. 7. The method of claim 1, wherein the predetermined threshold is a multiple of a maximum allowable power of the base station. 8. A method for avoiding power interruption of a base station in a mobile phone system utilizing variable rate transmission, the method comprising the steps of: A) calculating a transmission power requirement forecast for each time slot in at least one future frame; B) identifying time slots having a transmit power requirement greater than a predetermined threshold; C) Select the time slot with the highest transmission power requirement; D) identifying the transmission channel for the selected time slot; E) ordering the identified transmission channels firstly by increasing the frame processing priority and secondly by reducing the associated transmission power; F) Applying a tag that temporarily indicates that the data in a transport channel to which the tag is applied will be discarded, and the selected transport channels for each identified transport channel are recalculated in the order of the sorted transport channels. The transmission power demand prediction of the timing slot until the transmission power demand prediction is equal to or less than a predetermined threshold; G) Temporarily remove the tags previously applied to each transport channel in the reverse order of the sorted transport channels, and recalculate the transmission power demand forecast after each consecutive tag removal, so as to determine whether any tag removal would cause the transmit power demand forecast to exceed the predetermined threshold; and H) Suppressing data transmission on any transport channel whose demarking would cause the transmission power demand forecast to exceed the predetermined threshold. 9. The method of claim 8, wherein the transmission power demand forecast for each time slot is calculated using information of a current frame. 10. The method of claim 9, wherein the transmission power demand prediction for each time slot is calculated based on the transmission power used during the current frame. 11. The method of Claim 8, wherein the predetermined threshold is based on a maximum allowable power of the base station. 12. The method of claim 11, wherein the predetermined threshold is a multiple of a maximum allowable power of the base station. 13. A system for avoiding power interruptions in a mobile phone system utilizing variable rate transmission, the system comprising: A) a radio network controller, wherein data is transmitted to a base station for at least one user; B) Wherein, the data transmitted from the radio network controller to the base station is assigned a frame processing priority and separated into transmission channels mapped to physical channels, and transmitted to the at least one user; and C) The base station is used to identify at least one time slot of a future frame with a predicted transmission power demand greater than a predetermined threshold, and optimize the transmission power of each identified time slot according to the predetermined threshold Demand Forecast. 14. The system according to claim 13, wherein the base station calculates a transmission power demand forecast for each time slot of the at least one future frame, and determines whether each transmission power demand forecast exceeds any time slot A predetermined threshold value of , and identifying time slots in at least one future frame with a transmission power demand prediction greater than a predetermined threshold value. 15. The system of claim 14, wherein the base station calculates the transmission power demand forecast for each time slot by using information available to the base station in a current frame. 16. The system of claim 15, wherein the base station calculates the transmission power demand forecast based on the transmission power used during the current frame period. 17. The system of claim 14, wherein the predetermined threshold is based on a maximum allowable power of the base station. 18. The system of claim 17, wherein the predetermined threshold is a multiple of a maximum allowable power of the base station. 19. The system according to claim 13, wherein the base station discards the data of the transmission channel based on the frame priority firstly, and secondly based on the relative transmission power of the transmission channel, so as to optimize The transmit power demand forecast. 20. The system of claim 19, wherein the base station determines which data to discard by the following steps: A) applying a tag to each combination of the transport channels, which temporarily indicates that the data of the transport channel to which the tag is applied will be discarded; and B) Selecting to discard data of transport channels constituting a transport channel combination that optimizes the transmission power demand predictor for each identified time slot according to the predetermined threshold. 21. The system of claim 13, wherein the base station optimizes the transmission power demand forecast by the following steps: A) identifying at least one transmission channel of the identified time slot; B) sorting the identified transmission channels firstly by increasing the frame processing priority and secondly by reducing the associated transmission power; C) Applying a tag temporarily indicates that the data of a transport channel to which the tag is applied will be discarded, and the selected transport channels for each identified transport channel are recalculated in the order of the sorted transport channels. the transmission power demand forecast for the time slot until the transmission power demand forecast is equal to or less than a predetermined threshold; D) Temporarily remove the tags previously applied to each transport channel in the reverse order of the sorted transport channels, and recalculate the transmission power demand forecast after each consecutive tag removal, so as to determine whether any tag removal would cause the transmit power demand forecast to exceed the predetermined threshold; and E) Suppressing data transmission on any transport channel whose demarking would cause the transmission power demand forecast to exceed the predetermined threshold.

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