CN1698321A - Multi-threshold scheduler for transmitting data packets to mobile terminals based on a relative throughput distribution range - Google Patents

Abstract

The present invention provides different scheduling criteria depending on overall system performance in an effort to maintain fairness among mobile terminals and sustain a required QoS level. The invention is particularly effective for multi-carrier systems, wherein scheduling must also take into consideration the carrier used to transmit the scheduled data. In one embodiment, the present invention determines the spread of throughput rates for all mobile terminals being served by a given base station and bases the scheduling criteria thereon. Preferably, a standard deviation calculation is used to measure the throughput spread. The standard deviation of throughput associated with a collective group of mobile terminals is indicative of the differences between the lowest and highest throughputs with respect to the average throughput for the collective group of mobile terminals.

Description

Translated fromChinese

用于基于一个相对的吞吐量分布范围将 数据分组传输至移动终端的多门限调度器Multi-threshold scheduler for transmitting data packets to mobile terminals based on a relative throughput distribution

本申请要求受益于2001年6月5号申请的临时序列号为60/296101的申请，其公开文本由此包括在此整体中作为参考。This application claims the benefit of provisional serial number 60/296,101, filed June 5, 2001, the disclosure of which is hereby incorporated by reference in its entirety.

发明领域field of invention

本发明涉及无线通信，并尤其涉及调度用于从一个基站向一个或多个移动终端传输的数据。The present invention relates to wireless communications, and more particularly to scheduling data for transmission from a base station to one or more mobile terminals.

本发明技术背景Technical background of the present invention

分配例如时间或频率的通信资源的无线通信网络需要一个调度器(scheduler)以选择要发射的数据。当多个用户竞争这些资源时，调度器必须分析输入的数据，并确定具有最高传输优先级的数据。传统地，优先级是基于最大化整体系统的吞吐量(throughput)或维持特定的服务质量(QoS)水平以确保以及时的方式传输数据。当最大化吞吐量时，具有较好的信道条件的用户比具有较差的信道条件的用户更有优势。因此具有较为不利的信道条件的用户通常被赋予较低的优先级。结果，那些具有差的信道条件的用户倾向于较低的QoS水平。相反尽量保持特定的QoS水平经常导致不必要的低的系统吞吐量。A wireless communication network that allocates communication resources such as time or frequency requires a scheduler to select data to be transmitted. When multiple users compete for these resources, the scheduler must analyze the incoming data and determine the data with the highest transmission priority. Prioritization has traditionally been based on maximizing overall system throughput or maintaining a certain quality of service (QoS) level to ensure data is delivered in a timely manner. Users with better channel conditions have an advantage over users with poorer channel conditions when maximizing throughput. Users with less favorable channel conditions are therefore generally given lower priority. As a result, those users with poor channel conditions tend to have lower QoS levels. Trying to maintain a specific QoS level instead often results in unnecessarily low system throughput.

很多调度器单独地基于从移动终端反馈的信息中导出的载波对干扰比率(CIRs)对分组区分优先顺序。这些调度器最大化系统吞吐量而不考虑公平或最小吞吐量要求，并典型地为最靠近基站的用户调度传输。试图提供某种程度的公平的调度器使用导致差的系统吞吐量的基本调度标准。在支持多媒体无线互联网服务方面现有的调度器还有很多问题。进一步，大多数调度器并非为多载波操作而设计，这使得它们不适合多载波-数据和语音(MC-DV)环境。Many schedulers prioritize packets solely based on carrier-to-interference ratios (CIRs) derived from information fed back from mobile terminals. These schedulers maximize system throughput without regard to fairness or minimum throughput requirements, and typically schedule transmissions for users closest to the base station. Attempts to provide some degree of fairness to the scheduler use the underlying scheduling criteria resulting in poor system throughput. Existing schedulers still have many problems in supporting multimedia wireless Internet services. Further, most schedulers are not designed for multi-carrier operation, which makes them unsuitable for multi-carrier-data and voice (MC-DV) environments.

这些现有的调度技术未能提供一个自适应的调度标准，其能够进化以满足无线通信环境不断变化的需求以在确保用户间某种程度的公平的同时优化吞吐量。因此，当在用户间确保公平时，需要自适应调度技术以优化吞吐量。为了在维护所期望的公平程度的同时最大化整体系统的吞吐量，对于这些能够优化多载波分集的调度技术还存在进一步的需求。These existing scheduling techniques fail to provide an adaptive scheduling criterion that can evolve to meet the changing needs of the wireless communication environment to optimize throughput while ensuring some degree of fairness among users. Therefore, adaptive scheduling techniques are needed to optimize throughput while ensuring fairness among users. There is a further need for these scheduling techniques that can optimize multi-carrier diversity in order to maximize overall system throughput while maintaining the desired degree of fairness.

发明概述Summary of the invention

取决于在移动终端中维护公平以及维持要求的QoS水平的整体系统表现，本发明提供了不同的调度标准。本发明对多载波系统特别有效，其中调度也必须考虑用于发射调度的数据的载波。在一个实施例中，本发明为所有由给定的基站服务的移动终端确定吞吐率的分布范围，并以在其上的调度标准作为基础。优选地，可利用标准偏差计算来测量吞吐量的分布范围。与移动终端集体组(collective group)相关的吞吐量的标准偏差表示了关于移动终端的集体组的平均吞吐量在最低和最高的吞吐量之间的差异。Depending on the overall system performance in maintaining fairness in the mobile terminals and maintaining the required QoS level, the present invention provides different scheduling criteria. The invention is particularly effective for multi-carrier systems, where scheduling must also take into account the carrier used to transmit the scheduled data. In one embodiment, the present invention determines a distribution of throughput rates for all mobile terminals served by a given base station, and bases the scheduling criteria thereon. Preferably, the distribution of throughput can be measured using standard deviation calculations. The standard deviation of the throughput associated with the collective group of mobile terminals represents the difference between the lowest and the highest throughput of the average throughput with respect to the collective group of mobile terminals.

与高标准偏差关联的吞吐量表示某些移动终端正在经历很低的吞吐量，而同时其它的终端正在经历相对高的吞吐量，并且不公平调度的潜在可能性增加了。同样地，用于在累积的吞吐量尝试中较高的标准偏差的调度标准是在较低吞吐量的移动终端上增添较高的优先级。相反，随着标准偏差降低，当大部分移动终端的吞吐量接近平均的累积吞吐量，调度标准应当着重整体的吞吐量，并因此为可最大化吞吐量的移动终端选择调度，而不是确保具有较低的吞吐量的移动终端得到公平对待。A throughput associated with a high standard deviation indicates that some mobile terminals are experiencing very low throughput while other terminals are experiencing relatively high throughput, and the potential for unfair scheduling increases. Likewise, the scheduling criterion for higher standard deviations in cumulative throughput attempts is to place higher priority on lower throughput mobile terminals. Conversely, as the standard deviation decreases, when the throughput of most mobile terminals is close to the average cumulative throughput, the scheduling criterion should focus on the overall throughput, and thus choose scheduling for mobile terminals that can maximize throughput, rather than ensuring that there is Lower throughput mobile terminals are treated fairly.

当尝试最大化吞吐量时，可使用最大的载波对干扰比率(CIR)调度，其中基于CIR等为一个与最有利的信道条件相关的载波和移动终端的组合调度数据。可选地，可使用成比例的公平调度代替或结合最大CIR调度。成比例的公平调度通过使用与最强的信号电平相关的载波调度至移动终端的传输，以尝试利用信道的时间变化。那些本领域的技术人员将可识别与本发明的概念相兼容的其它的调度标准。When trying to maximize throughput, maximum Carrier-to-Interference Ratio (CIR) scheduling can be used, where data is scheduled for a carrier and mobile terminal combination associated with the most favorable channel conditions based on CIR, etc. Alternatively, proportional fair scheduling can be used instead of or in conjunction with max-CIR scheduling. Proportional fair scheduling attempts to take advantage of the temporal variation of the channel by scheduling transmissions to mobile terminals using the carrier associated with the strongest signal level. Those skilled in the art will recognize other scheduling criteria that are compatible with the concepts of the present invention.

在阅读了下面结合附图的优选实施例的详细描述之后，本领域的技术人员将认识到本发明的范围并意识到本发明的其他方面。Those skilled in the art will appreciate the scope of the present invention and realize other aspects of the invention after reading the following detailed description of the preferred embodiment taken in conjunction with the accompanying drawings.

附图说明Description of drawings

包括在说明书中并形成了此说明书的一部分的附图说明了本发明的几个方面，并与描述一起解释了本发明的原理。The accompanying drawings, which are incorporated in and form a part of this specification, illustrate several aspects of the invention and together with the description explain the principles of the invention.

图1是依据本发明的一个实施例的无线通信环境的框图表示。Figure 1 is a block diagram representation of a wireless communication environment in accordance with one embodiment of the present invention.

图2是依据本发明的一个实施例的流程图Fig. 2 is a flowchart according to an embodiment of the present invention

图3A到3D说明了依据本发明的一个实施例的四种调度模式。3A to 3D illustrate four scheduling modes according to one embodiment of the present invention.

优选实施例的详细描述Detailed description of the preferred embodiment

下面说明的实施例提供了可使得本领域的技术人员实现本发明的必要信息，并说明了实现本发明的最优的方式。根据附图读了下面的描述后，那些本领域的技术人员就可以理解本发明的概念，并认识到这些概念的应用不仅在于这里所特别描述的。可以理解这些概念和应用落入公开的文本和附属的权利要求的范围。The embodiments described below provide the necessary information to enable those skilled in the art to practice the invention and illustrate the best mode for carrying out the invention. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art can understand the concepts of the invention and realize applications of these concepts beyond what has been specifically described herein. It is understood that these concepts and applications fall within the scope of the disclosed text and appended claims.

参照图1，无线网络在选择的覆盖区域或小区内使用例如基站10的接入点，以协助与例如移动终端12的接入终端进行通信。基站10的各个组都由通信网络14所支持，此网络可包括移动交换中心，公共交换电话网(PSTN)，分组交换网或以上的组合。通信网络14用于从或向基站10传送分组。分组可以以直接分组交换的方式或在电路交换的平台顶端上进行通信。对于本发明而言，分组以何种方式传送到基站10并不是关键的。Referring to FIG. 1 , a wireless network employs access points, such as base stations 10 , to facilitate communication with access terminals, such as mobile terminals 12 , within selected coverage areas or cells. Each group of base stations 10 is supported by a communications network 14, which may include a mobile switching centre, public switched telephone network (PSTN), packet switched network or a combination thereof. Communication network 14 is used to communicate packets from or to base station 10 . Packets can be communicated in a direct packet-switched manner or on top of a circuit-switched platform. The manner in which the packets are delivered to the base station 10 is not critical to the invention.

在从基站10到选择的移动终端12的前向链路通信期间，基站10必须确定把从通信网络14接收到的分组中的数据发射到移动终端12的方式和顺序。在多载波系统中，基站10也需要确定传输分组的载波或信道。因此，基站10将包括具有控制平面18的控制系统16，控制平面控制通过数据平面20的数据流。为了与移动终端12通信，在控制平面18的控制下，数据平面20将处理通过网络接口22从通信网络14接收到的分组。分组被处理成单元，它们被送到无线电频率(RF)收发信机电路24进行传输。为了清楚起见，术语“分组”指由基站10从通信网络14接收的分组数据。术语“单元”指从基站10向移动终端12发射的分组数据。一个单元可包括一个或多个分组的所有或任何部分。尽管单元可直接相应于分组，但是单元更适宜地是给定的大小，其中分组的大小可以各不相同。单元可包括语音，视频，或传统的数据。During forward link communications from base station 10 to selected mobile terminals 12, base station 10 must determine the manner and order in which to transmit data in packets received from communication network 14 to mobile terminals 12. In a multi-carrier system, the base station 10 also needs to determine the carrier or channel on which to transmit the packet. Accordingly, the base station 10 will include a control system 16 having a control plane 18 that controls the flow of data through a data plane 20 . In order to communicate with the mobile terminal 12 , under the control of the control plane 18 , the data plane 20 will process packets received from the communication network 14 through the network interface 22 . Packets are processed into units, which are sent to radio frequency (RF) transceiver circuitry 24 for transmission. For clarity, the term "packet" refers to packet data received by base station 10 from communication network 14 . The term “unit” refers to packet data transmitted from the base station 10 to the mobile terminal 12 . A unit may include all or any part of one or more packets. The cells are preferably of a given size, although the cells may correspond directly to the packets, where the packets may vary in size. Units can include voice, video, or traditional data.

从基站10到选择的移动终端12的前向链路可包括一个或多个信道，这些信道可被分成规定的时隙。RF收发信机电路24配置为调制由控制平面18指示的给定的单元，并在一个单个时隙内通过一个或多个天线26发射调制的单元。RF收发信机电路24优选地配置为基于信道的条件，移动终端12的容量，或要求的传输标准而执行不同的调制合编码技术。正如所注释的，RF收发信机电路24可通过多个不同的载波发射单元。那些本领域的技术人员将可认识到各种可能的调制技术，以及在给定的时隙内可以发射多个单元。The forward link from base station 10 to selected mobile terminals 12 may include one or more channels, which may be divided into defined time slots. The RF transceiver circuitry 24 is configured to modulate a given cell as directed by the control plane 18 and to transmit the modulated cell via one or more antennas 26 within a single time slot. The RF transceiver circuitry 24 is preferably configured to implement different modulation and coding techniques based on channel conditions, capabilities of the mobile terminal 12, or required transmission standards. As noted, the RF transceiver circuitry 24 may transmit units through a number of different carriers. Those skilled in the art will recognize the various modulation techniques possible, and that multiple units may be transmitted in a given time slot.

控制平面18包括一个调度器28，该调度器被配置为基于下面将进一步详细说明参数进行排序，并控制把单元发送到移动终端12的顺序。在操作期间，接收用于任何数量的移动终端12的分组，并将分组存储到与数据平面20相关联的缓冲器30中。缓冲器30被分离成多个队列，每个队列与给定的移动终端12相关联。如果分组不直接对应于单元，输入的分组被处理成期望的单元。单元按它们被接收到的顺序被存储在各个相应的队列，优选地，队列使用先进先出(FIFO)的配置。The control plane 18 includes a scheduler 28 configured to sequence and control the order in which cells are sent to the mobile terminals 12 based on parameters described in further detail below. During operation, packets for any number of mobile terminals 12 are received and stored into buffers 30 associated with data plane 20 . The buffer 30 is divided into a plurality of queues, each queue being associated with a given mobile terminal 12 . If the packet does not directly correspond to a unit, the incoming packet is processed into the desired unit. Units are stored in respective queues in the order in which they are received, preferably the queues use a first in first out (FIFO) configuration.

取决于维护在移动终端12之间的公平和维持要求的QoS水平的整体系统的表现，本发明提供了不同调度标准。本发明对于多载波系统特别有效，其中调度必须考虑用于发射调度后的数据的载波。在一个实施例中，本发明为所有的由给定的基站10服务的移动终端12确定吞吐率的分布范围，并以此做为调度标准的基础。优选地，使用标准偏差计算以测量吞吐量的分布范围。与移动终端12的集体组相关的吞吐量的标准偏差表示了关于移动终端12的集体组的平均吞吐量在最低和最高的吞吐量之间的差异。因此，与高标准偏差关联的吞吐量表示某些移动终端12正在经历很低的吞吐量，而某些正在经历很高的吞吐量，并且不公平调度的潜在可能性增加了。同样地，用于在累积的吞吐量尝试中更高的标准偏差的调度标准是在较低吞吐量的移动终端12上增添更高的优先级。相反，随着标准偏差降低，当大部分移动终端的吞吐量接近平均的累积吞吐量时，调度标准应当着重整体的吞吐量，并因此为可最大化吞吐量的移动终端选择调度，而不是确保具有较低的吞吐量的移动终端12得到公平地对待。Depending on the performance of the overall system to maintain fairness among the mobile terminals 12 and to maintain the required QoS level, the present invention provides different scheduling criteria. The invention is particularly effective for multi-carrier systems, where scheduling must take into account the carrier used to transmit the scheduled data. In one embodiment, the present invention determines a throughput distribution range for all mobile terminals 12 served by a given base station 10, and uses this as the basis for scheduling criteria. Preferably, a standard deviation calculation is used to measure the distribution of throughput. The standard deviation of the throughput associated with the collective group of mobile terminals 12 represents the difference between the lowest and the highest throughput for the average throughput of the collective group of mobile terminals 12 . Thus, a throughput associated with a high standard deviation indicates that some mobile terminals 12 are experiencing very low throughput, while some are experiencing very high throughput, and the potential for unfair scheduling increases. Likewise, the scheduling criterion for higher standard deviations in cumulative throughput attempts is to place higher priority on lower throughput mobile terminals 12 . Conversely, as the standard deviation decreases, when the throughput of most mobile terminals is close to the average cumulative throughput, the scheduling criterion should focus on the overall throughput, and thus choose scheduling for the mobile terminals that can maximize the throughput, rather than ensuring that Mobile terminals 12 with lower throughput are treated fairly.

在根据本发明的一个实施例的示范过程的概述之后将提供进一步的细节。参照图2的流程图，根据一个实施例说明调度器28的操作。在一个正在进行的基础上，将发射的单元放置在用于相应的移动终端12的队列中(步骤100)。进一步，当从移动终端12报告返回时，调度器28可为每个载波和每个移动终端12连续地监测信道条件(步骤102)。一般地，信道条件表示用于多载波中每一个从基站10到移动终端12的传输信道的质量。吞吐率可以是实际或估算的数据吞吐率，信道条件或它们的组合的函数。Further details will be provided following an overview of an exemplary process according to one embodiment of the invention. Referring to the flowchart of FIG. 2, the operation of the scheduler 28 is illustrated according to one embodiment. On an ongoing basis, the transmitted unit is placed in a queue for the corresponding mobile terminal 12 (step 100). Further, the scheduler 28 may continuously monitor channel conditions for each carrier and each mobile terminal 12 as reports come back from the mobile terminals 12 (step 102). In general, the channel condition represents the quality of the transmission channel from the base station 10 to the mobile terminal 12 for each of the multiple carriers. Throughput may be a function of actual or estimated data throughput, channel conditions, or a combination thereof.

信道条件可连续变化并可使用任何数量的技术确定。例如，载波对干扰比率(CIR)，它表示了载波信号能量对干扰能量的度量，可从移动终端12反馈给基站10。调度器28将优选地为每个载波和移动终端12连续地跟踪信道条件。调度器28也将为每个移动终端12监测吞吐量(步骤104)。Channel conditions can vary continuously and can be determined using any number of techniques. For example, a carrier-to-interference ratio (CIR), which represents a measure of carrier signal energy to interference energy, may be fed back from mobile terminal 12 to base station 10 . The scheduler 28 will preferably continuously track channel conditions for each carrier and mobile terminal 12 . The scheduler 28 will also monitor the throughput for each mobile terminal 12 (step 104).

假设基站10为M个有效的移动终端12服务。在时隙n用于所有移动终端12的累积的吞吐量由向量Λ(n)表示，如Assume that the base station 10 serves M active mobile terminals 12 . The cumulative throughput for all mobile terminals 12 at time slot n is represented by the vector Λ(n), as

等式1Equation 1

      Λ(n)＝[Λ₀x(n)，Λ₁(n)，…，Λ_M-1(n)]Λ (n)=[_Λ0x (n),_Λ1 (n), ..., ΛM_-1 (n)]

由于信道变异，例如路径损耗，阴影衰退和Rayleigh衰减，吞吐量的显著变化将在任何给定的时间在不同的移动终端12之间出现。这些变化严重地降低了吞吐性能和与之相关的QoS。为了评估吞吐量性能，确定了在时隙n用于所有移动终端12的累积的吞吐量的标准偏差，σ_th(n)。累积的吞吐量的标准偏差，σ_th(n)定义如下：Due to channel variations such as path loss, shadow fading and Rayleigh fading, significant variations in throughput will occur between different mobile terminals 12 at any given time. These changes severely degrade throughput performance and the associated QoS. To evaluate the throughput performance, the standard deviation of the accumulated throughput, σ_th (n), for all mobile terminals 12 at time slot n is determined. The standard deviation of the cumulative throughput, σ_th (n), is defined as follows:

等式2Equation 2

其中μ(n)是时隙n的累积的吞吐量的均值，可由等式3给出：where μ(n) is the mean value of the accumulated throughput for slot n, given by Equation 3:

等式3$\mathrm{\μ}\left(n\right)=\frac{1}{M}\underset{m=0}{\overset{M-1}{\mathrm{\Σ}}}{\mathrm{\Λ}}_m$Equation 3$\mathrm{\μ}\left(\mathrm{no}\right)=\frac{1}{m}\underset{m=0}{\overset{m-1}{\mathrm{\Σ}}}{\mathrm{\Λ}}_m$

为了计算标准偏差σ_th(n)，每个移动终端12使用N通用导频信号监测N个独立载波的信道条件，并确定N个独立的CIR。CIR然后被发送到基站10。基站10将生成CIR矩阵，Γ(n)(步骤106)，它可表示为To calculate the standard deviation σ_th (n), each mobile terminal 12 monitors the channel conditions of N independent carriers using N common pilot signals and determines N independent CIRs. The CIR is then sent to the base station 10 . The base station 10 will generate a CIR matrix, Γ(n) (step 106), which can be expressed as

等式4Equation 4

基于与每个信道条件相关联的自适应的调制和编码(AMC)，CIR矩阵可映射为传输速率矩阵，R，它表示了用于每个移动终端12和每个载波的可能的吞吐量(步骤108)，传输速率矩阵R可表示为Based on the adaptive modulation and coding (AMC) associated with each channel condition, the CIR matrix can be mapped into a transmission rate matrix, R, which represents the possible throughput for each mobile terminal 12 and each carrier ( Step 108), the transmission rate matrix R can be expressed as

等式5Equation 5

通过使用合成的传输速率矩阵R(n)，以及最大CIR用户调度，调度器28可估算在下一个时隙n的累积的用户吞吐量(步骤110)，如由等式6所给出的Using the resulting transmission rate matrix R(n), and the maximum CIR user schedule, the scheduler 28 can estimate the cumulative user throughput at the next time slot n (step 110), as given by Equation 6

等式6$\underset{\‾}{\overset{^}{\mathrm{\Λ}}}\left(n\right)=\left[\begin{array}{cccc}{\widehat{\mathrm{\Λ}}}_0\left(n\right),& {\widehat{\mathrm{\Λ}}}_1\left(n\right),& \·\·\·& {\widehat{\mathrm{\Λ}}}_{M-1}\left(n\right)\end{array}\right]$Equation 6$\underset{\‾}{\overset{^}{\mathrm{\Λ}}}\left(\mathrm{no}\right)=\left[\begin{array}{cccc}{\widehat{\mathrm{\Λ}}}_0\left(\mathrm{no}\right),& {\widehat{\mathrm{\Λ}}}_1\left(\mathrm{no}\right),& \&Center\; Dot;\&Center\; Dot;\&Center\; Dot;& {\widehat{\mathrm{\Λ}}}_{m-1}\left(\mathrm{no}\right)\end{array}\right]$

其中in

等式7${\widehat{\mathrm{\Λ}}}_m\left(n\right)={\mathrm{\Λ}}_m(n-1)+\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}{\mathrm{\α}}_{k,m}\left(n\right)\·R_{k,m}\left(n\right)$Equation 7${\widehat{\mathrm{\Λ}}}_m\left(\mathrm{no}\right)={\mathrm{\Λ}}_m(\mathrm{no}-1)+\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}{\mathrm{\α}}_{k,m}\left(\mathrm{no}\right)\·R_{k,m}\left(\mathrm{no}\right)$

并且其中对于第m个用户的第k个有效载波而言α_k，m(n)＝1，并且对于第m个用户的第k无效载波α_k，m(n)＝0。或对于第m个用户的第k个有效载波α_k，m(n)＝p，而对于第m个用户的第k个无效载波α_k，m(n)＝1-p，p是小于单元的正数。使用估算的吞吐量

调度器28可以很容易地获得估算的吞吐量的标准偏差

(步骤112)，并接着使用基于估算的吞吐量的标准偏差

选择的调度标准对用于选择的移动终端12的传输的单元和在选择的载波上进行调度(步骤114)。And wherein α_k,m (n)=1 for the k-th active carrier of the m-th user, and α_k,m (n)=0 for the k-th invalid carrier of the m-th user. Or for the k-th effective carrier α_{k of the m-th user, m} (n) = p, and for the k-th invalid carrier α_{k of the m-th user, m} (n) = 1-p, p is less than the unit positive number of . Use estimated throughput

The scheduler 28 can easily obtain the standard deviation of the estimated throughput

(step 112), and then use the standard deviation based on the estimated throughput

The selected scheduling criteria schedules units for transmission by the selected mobile terminal 12 and on the selected carrier (step 114).

例如，下面详细说明一个在三载波环境中的多门限(N＝3)自适应调度标准。有三个门限值，就有了调度标准的四个分类。在该例子中，最大的CIR调度指示调度器将系统地选择具有最大CIR的载波和移动终端12直到每个可用的载波具有一个已调度的用于在给定的时隙n中传输的单元。下面是结合图3A-3D的示范性的调度标准：For example, a multi-threshold (N=3) adaptive scheduling criterion in a three-carrier environment is described in detail below. With three thresholds, there are four classifications of scheduling criteria. In this example, the largest CIR schedule indicates that the scheduler will systematically select the carrier and mobile terminal 12 with the largest CIR until each available carrier has a unit scheduled for transmission in a given time slot n. The following are exemplary scheduling criteria in conjunction with FIGS. 3A-3D :

●如果${\widehat{\mathrm{\σ}}}_{\mathrm{th}}\left(n\right)\≤{\mathrm{\σ}}_1^{\left(\max \right)},$为三个载波中的每一个使用最大CIR调度(图3A)。●If${\widehat{\mathrm{\σ}}}_{\mathrm{the\; th}}\left(\mathrm{no}\right)\≤{\mathrm{\σ}}_1^{\left(\max \right)},$ Maximum CIR scheduling is used for each of the three carriers (FIG. 3A).

●如果${\mathrm{\&sigma;}}_1^{\left(\max \right)}<{\widehat{\mathrm{\&sigma;}}}_{\mathrm{th}}\left(n\right)\&le;{\mathrm{\&sigma;}}_2^{\left(\max \right)},$确定一个具有最小接收到的吞吐量的移动终端12并在最优载波上为确定的移动终端12分配一个时隙。对剩余的两个载波使用最大CIR调度(图3B)。●If${\mathrm{\&sigma;}}_1^{\left(\max \right)}<{\widehat{\mathrm{\&sigma;}}}_{\mathrm{the\; th}}\left(\mathrm{no}\right)\&le;{\mathrm{\&sigma;}}_2^{\left(\max \right)},$ A mobile terminal 12 having the smallest received throughput is determined and a time slot is assigned to the determined mobile terminal 12 on the optimal carrier. Use maximum CIR scheduling for the remaining two carriers (FIG. 3B).

●如果${\mathrm{\&sigma;}}_2^{\left(\max \right)}<{\widehat{\mathrm{\&sigma;}}}_{\mathrm{th}}\left(n\right)\&le;{\mathrm{\&sigma;}}_3^{\left(\max \right)},$确定两个具有最小接收到的吞吐量的移动终端12并在第一和第二最优载波上为这些移动终端12分配两个时隙。对剩余的载波使用最大CIR调度(图3C)；以及●if${\mathrm{\&sigma;}}_2^{\left(\max \right)}<{\widehat{\mathrm{\&sigma;}}}_{\mathrm{the\; th}}\left(\mathrm{no}\right)\&le;{\mathrm{\&sigma;}}_3^{\left(\max \right)},$ Two mobile terminals 12 with the smallest received throughput are determined and assigned two time slots on the first and second optimal carriers. Use maximum CIR scheduling for the remaining carriers (FIG. 3C); and

●如果${\widehat{\mathrm{\&sigma;}}}_{\mathrm{th}}\left(n\right)>{\mathrm{\&sigma;}}_3^{\left(\max \right)},$确定三个具有最小接收到的吞吐量的移动终端12并在这些载波上为这些移动终端12分配三个时隙。不再使用最大CIR调度(图3D)。●if${\widehat{\mathrm{\&sigma;}}}_{\mathrm{the\; th}}\left(\mathrm{no}\right)>{\mathrm{\&sigma;}}_3^{\left(\max \right)},$ Three mobile terminals 12 with the smallest received throughput are determined and assigned three time slots on these carriers. Maximum CIR scheduling was no longer used (Fig. 3D).

这里σ_k^(max)是吞吐量标准偏差的门限值，由此流服务性能可以很容易地被控制在一个期望的σ_N^(max)水平下，k＝1，2，….，N。Here σ_k^(max) is the threshold value of the standard deviation of the throughput, so that the streaming service performance can be easily controlled at a desired σ_N^(max) level, k=1, 2, . . . , N.

为了定义吞吐量标准偏差的门限值σ_k^(max)，设置了两个变量σ_L和σ_H。如果${\widehat{\mathrm{\&sigma;}}}_{\mathrm{th}}\left(n\right)<{\mathrm{\&sigma;}}_L,$应该使用最大CIR调度，而如果${\widehat{\mathrm{\&sigma;}}}_{\mathrm{th}}\left(n\right)>{\mathrm{\&sigma;}}_H,$则不得不终止最大CIR调度。例如，基于σ_L和σ_H，确定吞吐量σ_k^(max)标准偏差的门限值，并且可表示为：In order to define the threshold σ_k^(max) of the throughput standard deviation, two variables σ_L and σ_H are set. if${\widehat{\mathrm{\&sigma;}}}_{\mathrm{the\; th}}\left(\mathrm{no}\right)<{\mathrm{\&sigma;}}_L,$ Should use maximum CIR scheduling, and if${\widehat{\mathrm{\&sigma;}}}_{\mathrm{the\; th}}\left(\mathrm{no}\right)>{\mathrm{\&sigma;}}_h,$ Then the maximum CIR scheduling has to be terminated. For example, based on σ_L and σ_H , the threshold value of the standard deviation of the throughput σ_k^(max) is determined, and can be expressed as:

等式8${\mathrm{\&sigma;}}_k^{\left(\max \right)}={\mathrm{\&sigma;}}_L+(k-1)\&CenterDot;\left(\frac{{\mathrm{\&sigma;}}_H-{\mathrm{\&sigma;}}_L}{N-1}\right),k=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;.,N.$Equation 8${\mathrm{\&sigma;}}_k^{\left(\max \right)}={\mathrm{\&sigma;}}_L+(k-1)\&Center\; Dot;\left(\frac{{\mathrm{\&sigma;}}_h-{\mathrm{\&sigma;}}_L}{N-1}\right),k=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;.,N.$

如上可见，本发明观察多个用户的吞吐量的分布范围以确定调度标准。随着分布范围的降低，CIR调度量增加。随着分布范围的增加，在调度中，优先考虑较低的吞吐量的移动终端。尽管上面的例子执行标准偏差以为每个移动终端12的吞吐量的相对分布范围提供统计分析，本领域的技术人员将认识到可采用其他技术和算法用于分析吞吐量的相对分布范围和选择基于其上的标准。As can be seen above, the present invention observes the distribution range of the throughput of multiple users to determine the scheduling criteria. As the distribution range decreases, the amount of CIR scheduling increases. As the distribution range increases, mobile terminals with lower throughput are given priority in scheduling. Although the above example implements standard deviation to provide a statistical analysis of the relative distribution of throughput for each mobile terminal 12, those skilled in the art will recognize that other techniques and algorithms may be employed for analyzing the relative distribution of throughput and selecting the relative distribution based on standards on it.

作为上述的最大CIR调度的备选，可使用成比例公平调度。成比例公平调度通过调度传输至移动终端12的使用与最强的信号电平关联的载波的传输，尝试利用信道的时间变化。例如，移动终端12可基于信号水平或信道质量请求某些数据速率，而基站10将基于请求的数据速率向移动终端12发送数据。当要求成比例公平调度时，将基于请求的数据速率与在一个给定的窗口上的平均的吞吐率的比率，调度传输至移动终端12的数据。后者有利于这些具有更好的发射大量数据的能力的移动终端。As an alternative to the max-CIR scheduling described above, proportionally fair scheduling can be used. Proportional fair scheduling attempts to take advantage of the temporal variation of the channel by scheduling transmissions to mobile terminals 12 using the carrier associated with the strongest signal level. For example, mobile terminal 12 may request certain data rates based on signal level or channel quality, and base station 10 will transmit data to mobile terminal 12 based on the requested data rate. When proportional fair scheduling is required, data transmission to mobile terminals 12 will be scheduled based on the ratio of the requested data rate to the average throughput rate over a given window. The latter is in favor of these mobile terminals which have a better ability to transmit large amounts of data.

本发明的这些方面可以使用可选择的不同于上面详细描述的等式和关系来实现。本领域的技术人员将认识到对本发明的优选实施例的改进和修改。所有这些改进和修改都被认为在这里公开的概念和后面的权利要求的范围中。These aspects of the invention can be implemented using alternative equations and relationships than those detailed above. Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the invention. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.

Claims (20)

1. method that is used to dispatch in wireless communications environment to the data of portable terminal transmission comprises:

A) determine throughput distribution relative among portable terminal;

B) from a plurality of scheduling standards, select one based on the throughput distribution; And

C) based on the scheduling standard of selecting the transmission of the unit that is used for some portable terminal is dispatched.

2. utilize in n the carrier wave one to communicate according to the process of claim 1 wherein with portable terminal.

3. according to the method for claim 2, one of them is used for the portable terminal that first standard-required of a plurality of scheduling standards of high throughput distribution selects at least one to be associated with lower throughput, and with carrier wave that best channel condition or peak signal level are associated on scheduling transfer to the transmission of the unit of at least one portable terminal.

4. according to the method for claim 3, one of them is used for second standard-required of a plurality of scheduling standards of lower throughput distribution and selects at least one remaining portable terminal, and with carrier wave that best channel condition or peak signal level are associated on scheduling transfer to the transmission of the unit of at least one portable terminal.

5. according to the method for claim 2, wherein:

A) first standard-required of a plurality of scheduling standards that are used for the poor throughput distribution with carrier wave that best channel condition or peak signal level are associated on scheduling transfer to the transmission of unit of the portable terminal of selection;

B) one be used in the middle of the intermediate standard of a plurality of scheduling standards of throughput distribution require to select at least one portable terminal that is associated with lower throughput, and with carrier wave that best channel condition or peak signal level are associated on dispatch the unit that transfers at least one portable terminal transmission; And

C) ultimate criterion of a plurality of scheduling standards that are used for the high-throughput distribution requires to select the portable terminal that is associated with minimum throughput, and with carrier wave that best channel condition or peak signal level are associated on dispatch the unit of the portable terminal that transfers to selection transmission.

6. according to the method for claim 2, wherein be used for the standard deviation calculation throughput distribution of the aggregated throughput of portable terminal by calculating.

7. according to the method for claim 6, further comprise:

A) determine the channel condition of each portable terminal and each carrier wave;

B) estimate the transmission rate of each portable terminal and each carrier wave based on corresponding channel condition and coding and modulation rate;

C) estimate the aggregated throughput of each portable terminal; And

D) determine the standard deviation of aggregated throughput.

8. according to the method for claim 2, wherein

A) one first scheduling standard is used maximum Carrier-to-Interface ratio or proportional equity dispatching to each carrier wave; And

B) one second at least one portable terminal that is associated with lower throughput of scheduling Standard Selection, and on a best available carrier wave, dispatch the unit transmission that is used for this at least one portable terminal, maximum Carrier-to-Interface ratio or proportional equity dispatching are used in the scheduling that wherein is used for remaining portable terminal.

9. method according to Claim 8, the scheduling that wherein is used for one the 3rd scheduling standard are selected n portable terminal with minimum throughput, and the unit of the portable terminal that scheduling is used to select on the available carrier wave of the best transmits.

10. a system that is used for scheduled transmission to the data of portable terminal in wireless communications environment comprises a control plane and scheduler, is suitable for:

A) determine throughput distribution relative among portable terminal;

B) from a plurality of scheduling standards, select one based on the throughput distribution; And

C) based on the scheduling standard of selecting the transmission of the unit that is used for some portable terminal is dispatched.

11., wherein utilize in n the carrier wave one to communicate with portable terminal according to the system of claim 10.

12. system according to claim 11, one of them is used for the portable terminal that first standard-required of a plurality of scheduling standards of high throughput distribution selects at least one to be associated with lower throughput, and with carrier wave that best channel condition or peak signal level are associated on scheduling transfer to the transmission of the unit of at least one portable terminal.

13. system according to claim 12, one of them is used for second standard-required of a plurality of scheduling standards of lower throughput distribution and selects at least one remaining portable terminal, and with carrier wave that best channel condition or peak signal level are associated on scheduling transfer to the transmission of the unit of at least one portable terminal.

14. according to the system of claim 11, wherein:

A) first standard-required of a plurality of scheduling standards that are used for the poor throughput distribution with carrier wave that best channel condition is associated on scheduling transfer to the transmission of unit of the portable terminal of selection;

B) one be used in the middle of the intermediate standard of a plurality of scheduling standards of throughput distribution require to select at least one portable terminal that is associated with lower throughput, and with carrier wave that best channel condition or peak signal level are associated on dispatch the unit that transfers at least one portable terminal transmission; And

D) ultimate criterion of a plurality of scheduling standards that are used for the high-throughput distribution requires to select the portable terminal that is associated with minimum throughput, and with carrier wave that best channel condition or peak signal level are associated on dispatch the unit of the portable terminal that transfers to selection transmission.

15., wherein be used for the standard deviation calculation throughput distribution of the aggregated throughput of portable terminal by calculating according to the system of claim 11.

16. according to the system of claim 15, wherein control plane and scheduler further are suitable for:

A) determine the channel condition of each portable terminal and each carrier wave;

B) estimate the transmission rate of each portable terminal and each carrier wave based on corresponding channel condition and coding and modulation rate;

C) estimate the aggregated throughput of each portable terminal; And

D) determine the standard deviation of aggregated throughput.

17. according to the system of claim 11, wherein

A) one first scheduling standard is used maximum Carrier-to-Interface ratio or proportional equity dispatching to each carrier wave; And

B) one second at least one portable terminal that is associated with lower throughput of scheduling Standard Selection, and the transmission of on the available carrier wave of a best, dispatching the unit that is used for this at least one portable terminal, maximum Carrier-to-Interface ratio or proportional equity dispatching are used in the scheduling that wherein is used for remaining portable terminal.

18. according to the system of claim 17, n portable terminal with minimum throughput selected in the scheduling that wherein is used for one the 3rd scheduling standard, and the unit of the portable terminal that scheduling is used to select on the available carrier wave of the best transmits.

19. a method that is used for scheduled transmission to the data of portable terminal in wireless communications environment comprises:

A) determine standard deviation in the throughput of the estimation in a continuous slot between a plurality of portable terminals on a plurality of carrier waves;

B) from a plurality of scheduling standards, select one based on standard deviation; And

C) based on each the scheduling standard of selecting of continuous slot that is used for a plurality of carrier waves, scheduling is used to write from memory the transmission of the unit of portable terminal.

20. method according to claim 19, in wherein a plurality of scheduling standards at least one is used at least one scheduling of a plurality of portable terminals with minimum throughput to be listed in preferentially, and is in one of them portable terminal that scheduling is a plurality of with best channel condition or peak signal level are associated of all the other carrier waves at least one.

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