WO2012119413A1 - 一种提高阅读器能效性能的方法及装置 - Google Patents

一种提高阅读器能效性能的方法及装置 Download PDF

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Publication number
WO2012119413A1
WO2012119413A1 PCT/CN2011/078851 CN2011078851W WO2012119413A1 WO 2012119413 A1 WO2012119413 A1 WO 2012119413A1 CN 2011078851 W CN2011078851 W CN 2011078851W WO 2012119413 A1 WO2012119413 A1 WO 2012119413A1
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value
slots
module
current
reader
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PCT/CN2011/078851
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English (en)
French (fr)
Inventor
薛涛
刘惠
杜军朝
刘树君
郭江坤
邓清哲
刘传益
贺文
李旋
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中兴通讯股份有限公司
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Priority to EP11860578.1A priority Critical patent/EP2669841B1/en
Priority to US14/003,251 priority patent/US9443120B2/en
Publication of WO2012119413A1 publication Critical patent/WO2012119413A1/zh

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
    • G06K7/10198—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves setting parameters for the interrogator, e.g. programming parameters and operating modes
    • G06K7/10207—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves setting parameters for the interrogator, e.g. programming parameters and operating modes parameter settings related to power consumption of the interrogator

Definitions

  • the present invention relates to the field of radio frequency identification (RFID) technology, and more particularly to a method and apparatus for improving the energy efficiency of a reader. Background technique
  • the RFID system can be composed of at least one reader and a tag, and the reader communicates with the tag wirelessly.
  • the inner valley of the institution is widely studied.
  • the main object of the present invention is to provide a method and apparatus for improving the energy consumption performance of a reader, so as to maximize the throughput of the RFID system, thereby reducing the energy consumption of the system and prolonging the use time of the system; At the same time, the rate at which the reader reads the label is guaranteed.
  • the present invention provides a method for improving energy efficiency of a reader, comprising: initializing and adjusting operational parameters to obtain a current number of frame slots; updating a frame slot state, and according to an updated frame slot State, determine that no power level needs to be increased; estimate the number of tags based on the number of current frame slots, and obtain the best Q value based on the number of tags.
  • the initializing and adjusting the operation parameters to obtain the current frame time slot quantity includes: initializing the operation parameter, and increasing the current power level in the operation parameter by an increment value, adding Q to 1 according to the current Q value and the frame time.
  • the slot number calculation formula obtains the number of current frame slots.
  • the method before the updating the frame slot state, the method further comprises: determining that the current power is less than or equal to the power maximum, updating the frame slot state; otherwise, estimating the number of tags according to the current frame slot number.
  • the updating the frame time slot state comprises: updating the number of idle time slots, the number of successful time slots, and the number of conflicting time slots according to the number of current frame time slots and the communication protocol between the reader and the tag.
  • the determining, according to the updated frame slot state, determining that the power level does not need to be increased includes: the number of collision slots is equal to 0, or the number of collision slots is greater than 0, and the number of successful slots is equal to 0, iteration after iteration The value is greater than the iterative maximum, then it is determined that there is no need to increase the power level.
  • the estimating the number of labels according to the current number of frame slots and obtaining the optimal Q value according to the number of labels includes: making the number of current frame slots equal to the total number of labels, and then mapping according to the total number of labels and the optimal Q value.
  • the table obtains the best Q value corresponding to the total number of the labels, and then sets the current Q value to the optimal Q value.
  • the present invention also provides an apparatus for improving energy efficiency of a reader, comprising: an initialization module, an adjustment module, a setting module, and an estimation module;
  • An initialization module configured to initialize an operation parameter, and notify an adjustment module
  • An adjustment module configured to adjust an operation parameter, obtain a current frame time slot quantity, and notify a setting module
  • a setting module configured to update a frame slot state, determine, according to a frame slot state, that the power level is not required to be increased, and send the current frame slot number to the estimating module; the notification includes the current frame slot number;
  • An estimation module configured to estimate the number of tags according to the number of frame slots, and obtain an optimal Q value according to the number of tags.
  • the initialization module is specifically configured to: initialize the adjustment module and set the operation parameter in the module; the adjustment module is specifically configured to: increase the current power level in the operation parameter by an increment value, add Q to 1, and then The current frame time slot number is obtained according to the current Q value and the number of frame time slots.
  • the adjusting module is further configured to: increase the current power level by an increment value, determine that the current power level is less than or equal to the maximum power level, and send the current frame time slot quantity to the setting module, otherwise, the current The number of frame slots is sent to the estimation module.
  • the setting module is specifically configured to update the number of idle time slots, the number of successful time slots, and the number of collision time slots according to the received number of current frame time slots and the communication protocol between the reader and the tag.
  • the setting module is specifically configured to: when the number of conflicting slots is 0, or the number of conflicting slots is greater than 0, and the number of successful slots is 0, determining that the iterative value after the iteration is greater than the iterative maximum, determining not Need to increase the power level.
  • the estimating module is specifically configured to: obtain the optimal Q value corresponding to the total number of labels according to the mapping relationship between the total number of labels and the optimal Q value, and obtain the optimal Q value corresponding to the total number of labels, and Set the Q value in the adjustment module to the optimal Q value.
  • the present invention first estimates the total number of tags, thereby obtaining the number of time slots, and reducing the power consumption while ensuring the rate at which the reader reads the tags.
  • Figure 1 is a schematic diagram of a device for obtaining energy from a passive tag
  • 2 is a diagram of a physical layer reaction rate detecting device
  • Figure 3 is a schematic diagram of the waveform of the physical layer in the loss state
  • FIG. 4 is a schematic flow chart of a method for improving energy efficiency of a reader according to the present invention.
  • Figure 5 is a schematic diagram showing the relationship between the total number of labels and the Q value
  • FIG. 6 is a schematic diagram of a mapping relationship between a power level and a tag response rate
  • Figure 7 is a schematic diagram showing the distribution of frame time slots in the process of communication between the reader and the tag;
  • FIG. 8 is a schematic diagram of the composition of an apparatus for improving energy efficiency of a reader according to the present invention. detailed description
  • the reader initializes and adjusts the operation parameters, obtains the current frame time slot number, updates the frame time slot state, determines that the power level does not need to be increased according to the frame time slot state, and estimates the total number of tags according to the current frame time slot number. And get the best Q value based on the total number of labels.
  • FIG. 1 The principle of the device for obtaining energy from passive tags is shown in Figure 1.
  • the reader When the reader is working, it continuously emits a set of electromagnetic waves of a fixed frequency.
  • the LC parallel resonant circuit in the tag When the tag is close to the reader, the LC parallel resonant circuit in the tag will resonate at the same frequency as the reader, so that the capacitor C Charging has a charge.
  • a unidirectional conductive charge pump is connected to store the charge in capacitor C to another capacitor C1.
  • capacitor C1 When capacitor C1 is charged to a certain voltage, this capacitor acts as a power source to supply operating voltages to other circuits on the tag, thereby enabling the data in the tag to be transmitted or received and saved by the reader.
  • the label can be divided into three states, namely, an idle state, that is, a state in which C1 is powered off; a lossy state, a state between C1 power-off and full-charge; and an active state, that is, C1 Fully charged state.
  • the reaction rate of the physical layer when the tag is communicated with the reader is measured by the olfactory detector.
  • the waveform of the physical layer measured by the olfactory detector By analyzing the waveform of the physical layer measured by the olfactory detector, it can be found that in three states: when the tag is idle, it cannot communicate with the reader; when the tag is in a lossy state, as shown in Figure 3, the lossy state
  • the label As shown in the physical layer waveform diagram, the label is in the form of a backscattered wave, when replying to the reader's query, because of the label's Insufficient energy can cause communication interruption with the reader, but the reader still waits for communication with the tag at the normal energy level, resulting in loss of energy in the reader; in active state, the reader communicates with the tag normally. , energy consumption is low.
  • FIG. 4 A method for improving the energy efficiency of a reader provided by the present invention is as shown in FIG. 4, and the specific steps are as follows:
  • Step 401 Initialize an operation parameter.
  • the reader sends an inquiry to the tag in the form of a scattered wave, the reader begins to communicate with the tag, determines that the tag has collided, and the reader initializes the operational parameters.
  • the reader determines that the label collides: According to the communication protocol between the reader and the tag, if the code received by the reader in the tag reply contains the reply failure message, it indicates that there is a collision between the tags, and there is a conflicting time slot. There are several reasons for the collision between the tags: the tag replies to the reader in the same time slot; or the tag is in a lossy state, the energy is insufficient to cause the reply to be interrupted; or the tag is damaged, and the reply message is incorrect.
  • the initialization operation parameter process includes: the reader sets the current power level P to Wherein, the minimum power level and the maximum power level P max hereinafter are determined by the reader's own power level range, while Xi is initialized to 0 and Q is initialized to 1.
  • the Xi is an iterative value
  • the Q is a quality factor of the reader antenna, which affects the transmission efficiency and throughput of the reader energy.
  • the value range of the Q is determined by the reader itself, and the throughput is the reader successfully reading the label. The probability.
  • Step 402 Adjust the operation parameter, obtain the current frame time slot quantity, and then determine whether the current power level is greater than the maximum power level. If yes, make the current power level the maximum power level, and then perform step 404. Otherwise, perform the step. 403;
  • the obtaining the number of current frame slots may be obtained according to a current Q value and a number of frame slots.
  • Step 403 update the frame time slot state, according to the frame time slot state, determine whether it is necessary to increase the current power level; if yes, go to step 402, otherwise, go to step 404;
  • the updating the frame time slot state includes: updating the number of idle time slots S Q , the number of successful time slots Si, and the number of collision time slots s 2 according to the number of current frame time slots and the communication protocol of the reader and the tag.
  • s 1 3 ⁇ 4 and s 2 include: First, the reader receives the reply of the tag. According to the communication protocol, if the code in the tag reply contains the reply failure message, indicating that there is a collision between the tags, the received reply containing the failure information is received. The number is the number of conflicting slots; likewise, the number of received replies containing success information is the number of successful slots; the number of current frame slots acquired, and the number of collision slots and the number of successful slots , the number of free slots can be obtained, and the number of idle slots
  • Determining whether the current power level needs to be increased according to the state of the frame slot includes: determining whether S 2 is 0. If S 2 is greater than 0, indicating that the label has collided at this time, further determining whether Si is greater than 0, and if 8 is greater than 0 , indicating that there are both conflicting time slots and successful time slots. To reduce the probability of collision time slots, you need to increase the current power level, which will be cleared, and then go to step 402. If 8 1 is equal to 0, the current conflict exists. Time slot, but there is no successful time slot, no tag communicates with the reader normally, the situation is abnormal, and it is judged whether the iterative value after iteration is greater than the iterative maximum value.
  • Step 404 The value is less than or equal to the iterative maximum value, indicating that the conflicting time slot has a reduced space, and step 402 is performed, the iteration maximum value X bound , according to the reader
  • the difference between the error rate setting and the probability limit of the error rate is X b .
  • the difference error rate is the probability of the reader reading the label incorrectly, according to Obtaining the actual measurement; determining whether the iterative value after the iteration is greater than the iterative maximum value includes:
  • Step 404 Estimate the total number of tags, and obtain an optimal Q value according to the total number of tags.
  • the total number of estimated tags includes: reading the number of current frame slots N s , according to the throughput calculation formula, the system can reach the maximum when N s is the same as the total number of tags Throughput, therefore, the total number of labels is the current number of frame slots.
  • the mapping relationship between the total number of labels and the optimal Q value is read, and the optimal Q value corresponding to the total number of labels is obtained, and the current Q value is set to Get the best Q value, you can get the maximum throughput, so that the current reader's energy consumption is the lowest.
  • the mapping relationship between the total number of labels and the optimal Q value can be obtained according to empirical measurements. As shown in FIG. 5, when the transmission rate of the reader and the label is 10 kbp, the mapping relationship between the total number of labels and the optimal Q value; The amount is the probability that the reader will successfully read the label, and the formula is calculated according to the throughput:
  • the response rate of the tag is kept at 100%, and the tag response rate and the power level are mapped as shown in FIG. 6, and the tag response rate is
  • the power level mapping relationship can be obtained empirically.
  • the response rate of the tag is 100%, and then the power level is increased, and the response rate of the tag remains unchanged.
  • the energy for the reader is a waste, according to The measurement results show that when the power level of the reader is at the critical point, the throughput of the system is the largest. Therefore, it can be seen that the solution of the present invention obtains the optimal Q value, maximizes the throughput of the system, and maintains the system.
  • the power level at the highest throughput allows the reader to consume the least amount of energy.
  • the description of the collision time slot, the success time slot, and the idle time slot is as shown in FIG. 7.
  • the reader issues a command to the tag, and the five tags are in the form of backscattered waves after receiving the command. Reply to the reader's inquiry. Since the reply of the tag is random, you can choose to respond in any time slot, so different tags may reply to the reader's inquiry in the same time slot, which will cause collision.
  • the time slot at this time is the conflict time slot, such as TS0, TS2, TS4, TS6 in the figure.
  • the tag replies to the reader's inquiry in the conflicting time slot. Due to the collision, the reader cannot read the tag correctly and the tag cannot be recognized by the reader.
  • Tags that are not recognized by the reader will continually select a new time slot to reply to the reader's query. If at a certain moment, only one tag responds in a time slot, then the reader can be successfully replied to the query.
  • the slot is the success slot, as shown in the figure, TS1, TS5, TS7, TS8, TS9.
  • the tag recognized by the reader is temporarily in a dormant state and will not preempt the time slot.
  • this time slot is the idle time slot, as shown in Figure TS3.
  • the present invention further provides an apparatus for improving the energy efficiency of the reader.
  • the apparatus includes: an initialization module 801, an adjustment module 802, a setting module 803, and an estimation module 804;
  • the initialization module 801 is configured to initialize the operation parameter, and notify the adjustment module 802 after the initialization is completed;
  • the adjusting module 802 is configured to adjust the operation parameter, obtain the current frame time slot quantity, determine that the current power level is less than or equal to the power level maximum value, notify the setting module 803, otherwise, make the current power level the maximum power level, notify
  • the estimating module 804 the adjusting the operating parameter comprises: increasing the current power level by an increment value, adding the current Q value by one; the notification includes the current frame time slot quantity;
  • the setting module 803 is configured to update the frame time slot state, determine the need to increase the power level according to the frame time slot state, notify the adjustment module 802; determine that the power level is not required to be increased, and send the current frame time slot number to the estimation module 804;
  • the estimating module 804 is configured to estimate the total number of labels according to the number of frame slots, and obtain an optimal Q value according to the total number of labels, and set the current Q value to the optimal Q value.
  • the setting module 803 is specifically configured to: read the number of current frame slots, and then update the number of idle slots, the number of successful slots, and the number of collision slots according to the number of frame slots and the communication protocol between the reader and the label; According to the number of frame time slots and the communication protocol between the reader and the tag, the reader receives the reply of the tag. According to the communication protocol, if the tag reply code contains the reply failure information, indicating that there is a collision between the tags, the received inclusion fails. The number of replies of the information is the number of conflicting slots; likewise, the number of replies received containing the success information is the number of successful slots; according to the number of current frame slots acquired, and the number of collision slots, The number of free slots can be obtained by the number of successful slots.
  • the setting module 803 is specifically configured to: when the number of conflicting time slots is 0, or the number of conflicting time slots is greater than 0, and the number of successful time slots is 0, determining that the iterative value after the iteration is greater than the maximum value of the iteration, determining that the power does not need to be increased Level
  • the estimating module 804 is specifically configured to: obtain the optimal Q value corresponding to the total number of labels according to the mapping relationship between the total number of labels and the optimal Q value, and obtain an optimal Q value according to the total number of labels and the optimal Q value, and adjust the module.
  • the Q value in the setting is set to the optimal Q value.

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Abstract

本发明公开了一种提高阅读器能效性能的方法，该方法包括：初始化并调整运算参数，获取当前帧时隙数量；更新帧时隙状态，并根据更新的帧时隙状态，确定不需要增加功率电平；根据当前帧时隙数量估算标签数量，并根据标签数量获取最佳Q值。本发明还公开了一种提高阅读器能效性能的装置，采用本发明所述的方法及装置，使RFID系统的吞吐量达到最大，从而降低了系统的能耗，延长系统的使用时间；在降低能耗的同时，保证了阅读器阅读标签的速率。

Description

一种提高阅读器能效性能的方法及装置 技术领域
本发明涉及射频识别 （RFID )技术领域， 特别是指一种提高阅读器能 效性能的方法及装置。 背景技术
RFID系统可以由至少一个阅读器和一个标签组成， 阅读器与标签通过 无线的方式进行通信。 近些年， 随着 RFID技术在物流、 库存管理、 零售、 公共交通等众多领域的广泛应用，如何提高 RFID系统性能，比如： 防沖撞、 阅读速率、 安全认证以及响应时间等， 是目前很多科研机构广泛研究的内 谷。
目前，尽管对 RFID系统性能的研究非常广泛，但是针对 RFID阅读器， 尤其是无源的便携式 RFID阅读器能量消耗问题的研究却非常少，在大型仓 库、 集装箱码头等应用场景中， 需要采用无源阅读器与标签进行通信， 靠 电池供电的无源阅读器如何尽可能多的阅读更多数量的标签， 成为我们要 关心和解决的问题。 发明内容
有鉴于此， 本发明的主要目的在于提供一种提高阅读器能耗性能的方 法及装置， 使 RFID系统的吞吐量达到最大， 从而降低系统的能耗， 延长系 统的使用时间； 并且在降低能耗的同时， 保证阅读器阅读标签的速率。
为解决上述技术问题， 本发明的技术方案是这样实现的：
本发明提供了一种提高阅读器能效性能的方法， 包括： 初始化并调整 运算参数， 获取当前帧时隙数量； 更新帧时隙状态， 并根据更新的帧时隙 状态， 确定不需要增加功率电平； 根据当前帧时隙数量估算标签数量， 并 根据标签数量获取最佳 Q值。
上述方案中， 所述初始化并调整运算参数， 获取当前帧时隙数量包括： 初始化运算参数， 并将运算参数中的当前功率电平增加递增值， 将 Q加 1 , 根据当前 Q值及帧时隙数量计算公式获取当前帧时隙数量。
上述方案中， 所述更新帧时隙状态之前， 该方法进一步包括： 确定当 前功率小于或等于功率最大值， 更新帧时隙状态； 否则， 根据当前帧时隙 数量， 估算标签数量。
上述方案中， 所述更新帧时隙状态包括： 根据当前帧时隙数量以及阅 读器与标签的通信协议， 更新空闲时隙数、 成功时隙数以及沖突时隙数。
上述方案中， 所述根据更新的帧时隙状态， 确定不需要增加功率电平 包括： 沖突时隙数等于 0, 或沖突时隙数大于 0且成功时隙数等于 0时， 迭 代后的迭代值大于迭代最大值， 则确定不需要增加功率电平。
上述方案中， 所述根据当前帧时隙数量估算标签数量， 并根据标签数 量获取最佳 Q值包括： 使当前帧时隙数量与标签总数相等， 然后根据标签 总数与最佳 Q值的映射关系表， 获取所述标签总数对应的最佳 Q值， 然后 设置当前的 Q值为最佳 Q值。
本发明还提供了一种提高阅读器能效性能的装置， 包括： 初始化模块、 调整模块、 设置模块以及估算模块；
初始化模块， 用于初始化运算参数， 并通知调整模块；
调整模块， 用于调整运算参数， 获取当前帧时隙数量， 并通知设置模 块；
设置模块， 用于更新帧时隙状态， 根据帧时隙状态确定不需要增加功 率电平， 将当前帧时隙数量发送给估算模块； 所述通知中包含当前帧时隙 数量； 估算模块， 用于根据帧时隙数量估算标签数量， 并根据标签数量获取 最佳 Q值。
上述方案中， 所述初始化模块具体用于， 初始化调整模块以及设置模 块中的运算参数； 所述调整模块具体用于， 将运算参数中的当前功率电平 增加递增值， 将 Q加 1 , 然后根据当前 Q值以及帧时隙数量计算公式获取 当前帧时隙数量。
上述方案中， 所述调整模块进一步用于， 将当前功率电平增加递增值， 确定当前功率电平小于或等于功率电平最大值， 将当前帧时隙数量发送给 设置模块， 否则， 将当前帧时隙数量发送给估算模块。
上述方案中， 所述设置模块具体用于， 根据接收的当前帧时隙数量以 及阅读器与标签的通信协议， 更新空闲时隙数、 成功时隙数以及沖撞时隙 数。
上述方案中， 所述设置模块具体用于， 沖突时隙数为 0, 或者沖突时隙 数大于 0, 且成功时隙数为 0时， 确定迭代后的迭代值大于迭代最大值， 则 确定不需要增加功率电平。
上述方案中， 所述估算模块具体用于， 将当前帧时隙数量等于标签总 数， 然后根据标签总数与最佳 Q值的映射关系表， 获取与所述标签总数对 应的最佳 Q值， 并将调整模块中的 Q值， 设置为最佳 Q值。
由此可见， 采用本发明所述的方法及装置， 在尽量减少标签沖撞的前 提下， 估算标签总数， 获取最佳 Q值， 可以使 RFID系统的吞吐量达到最 大， 从而降低了系统的能耗， 延长系统的使用时间； 同时， 本发明在降低 能耗时， 先估算标签总数， 从而获取何时的时隙数， 在降低能耗的同时， 保证了阅读器阅读标签的速率。 附图说明
图 1为被动式标签获得能量的装置原理图； 图 2为物理层反应速率探测装置图；
图 3为有损状态物理层波形示意图；
图 4为本发明实现提高阅读器能效性能的方法流程示意图；
图 5为标签总数与 Q值映射关系示意图；
图 6为功率电平与标签响应速率映射关系示意图；
图 7为阅读器与标签通信过程中帧时隙分布示意图；
图 8为本发明实现提高阅读器能效性能的装置组成示意图。 具体实施方式
本发明的基本思想是： 阅读器初始化并调整运算参数， 获取当前帧时 隙数量， 更新帧时隙状态， 根据帧时隙状态确定功率电平不需要增加， 根 据当前帧时隙数量估算标签总数， 并根据所述标签总数获取最佳 Q值。
被动式标签获得能量的装置原理如图 1 所示。 阅读器工作时， 不断地 向外发出一组固定频率的电磁波， 当有标签靠近阅读器时， 标签内的 LC并 联谐振电路会产生共振， 其频率与阅读器的发射频率相同， 从而使电容 C 充电有了电荷。在这个电容另一端，接有一个单向导电的电荷泵， 将电容 C 内的电荷送到另一个电容 C1内存储。 当电容 C1充电达到一定电压时， 此 电容作为电源， 为标签上的其他电路提供工作电压， 从而使标签内的数据 发射出去或接收阅读器发出的数据并保存。 其中， 根据充电过程， 可以将 标签分为三个状态， 分别为闲置状态， 即 C1断电的状态； 有损状态， 介于 C1断电与充满电之间的状态； 以及活跃状态， 即 C1充满电的状态。
根据如图 2所示的物理层反应速率探测装置， 通过嗅探测器对标签与 阅读器之间通信时的物理层的反应速率进行测量。 通过分析嗅探测器测量 的物理层的波形图可以发现， 在三个状态下： 标签处于闲置状态时， 无法 与阅读器通信； 标签处于有损状态时， 如图 3 所示的有损状态的物理层波 形图所示， 标签以反向散射波的形式， 回复阅读器的询问时， 因为标签的 能量不足， 会导致与阅读器之间的通信中断， 但是阅读器仍以正常状态的 能量电平等待与标签的通信， 导致阅读器的能量有损耗； 在活跃状态， 阅 读器与标签的通信正常， 能量消耗较低。
本发明提供的一种提高阅读器能效性能的方法， 如图 4所示， 具体步 驟如下：
步驟 401、 初始化运算参数；
阅读器以散射波的形式向标签发出询问， 阅读器与标签开始通信， 确 定标签发生沖撞， 阅读器初始化运算参数。
所述阅读器确定标签发生沖撞包括： 根据阅读器与标签之间的通信协 议， 若阅读器收到标签回复的代码中， 包含回复失败信息， 则说明标签之 间有沖撞， 存在沖突时隙。 所述标签之间有沖撞有以下几种原因： 标签在 同一时隙回复阅读器的询问； 或者标签处于有损状态， 能量不足导致回复 中断； 或者标签损坏， 回复信息错误。
所述初始化运算参数过程包括： 阅读器将当前功率电平 P 设置为
Figure imgf000007_0001
其中， 最小功率电平 以及下文中的最大功率电平 Pmax由阅 读器自身的功率电平范围决定， 同时， 将 Xi初始化为 0, 将 Q初始化为 1。 所述 Xi为迭代值， 所述 Q为阅读器天线的品质因素， 影响阅读器能量的传 输效率与吞吐量， Q 的取值范围由阅读器本身决定， 所述吞吐量为阅读器 成功阅读标签的概率。
步驟 402、 调整运算参数， 获取当前帧时隙数量， 然后确定当前功率电 平是否大于最大功率电平， 如果是， 使当前功率电平为最大功率电平， 然 后执行步驟 404, 否则， 执行步驟 403;
所述获取当前帧时隙数量， 可以根据当前 Q值以及帧时隙数量计算公 式获取。 所述帧时隙数量计算公式为： NS=2Q—公式 (1);
所述调整运算参数包括： 在当前功率电平上增加递增值， 同时将 Q值 加 1 ; 在当前功率电平 P上增加递增值， 假设递增值为 0.5 , 则 P=P+0.5 , 然后比较 P与最大功率电平 Pmax的大小， 若 P大于 Pmax, 根据当前 Q值及 公式 (1), 获取当前帧时隙数量， 执行步驟 404, 否则， 执行步驟 403。
步驟 403、 更新帧时隙状态， 根据帧时隙状态， 判断是否需要增加当前 功率电平； 如果是， 执行步驟 402, 否则， 执行步驟 404;
所述更新帧时隙状态包括： 根据当前帧时隙数量以及阅读器与标签的 通信协议更新空闲时隙数 SQ、 成功时隙数 Si以及沖撞时隙数 s2。
所述根据当前帧时隙数量以及阅读器与标签的通信协议更新 s。、 s1 ¾ 以及 s2包括： 首先， 阅读器接收标签的回复， 根据通信协议， 若标签回复 的代码中， 包含回复失败信息， 说明标签之间有沖撞， 则接收的包含失败 信息的回复的个数， 即为沖突时隙数； 同样的， 接收的包含成功信息的回 复的个数， 即为成功时隙数； 根据获取的当前帧时隙数量， 以及沖突时隙 数、 成功时隙数， 即可获取空闲时隙数， 所述空闲时隙数
Figure imgf000008_0001
所述根据帧时隙状态， 判断是否需要增加当前功率电平包括： 判断 S2 是否为 0, 若 S2大于 0, 说明标签此时发生了沖撞， 进一步判断 Si是否大 于 0, 若8 大于 0, 说明此时既有沖突时隙， 也有成功时隙， 为减少沖突时 隙发生的概率， 需要提高当前功率电平， 将 清零， 然后执行步驟 402; 若 81等于 0, 说明当前有沖突时隙， 但是没有成功时隙， 没有标签与阅读 器正常通信， 情况反常， 判断迭代后的迭代值是否大于迭代最大值， 若大 于迭代最大值， 说明功率电平已经增大到一定程度， 但是反常情况仍然存 在， 如果继续增大功率电平， 将导致系统的能耗太大， 为保证系统的吞吐 量， 尽量的降低能耗， 保留当前的沖突时隙的存在， 执行步驟 404; 若迭代 值小于或等于迭代最大值， 说明沖突时隙还有减小的空间， 执行步驟 402, 所述迭代最大值 Xbound , 根据阅读器的区别错误率设定， 区别错误率的概率 极限， 即为 Xb。und, 所述区别错误率为阅读器错误读取标签的概率， 可根据 实际测量获取； 所述判断迭代后的迭代值是否大于迭代最大值包括： 将
XpXi+Ι , 然后判断 与 xb。und的大小， 若 小于或等于 xb。und, 则迭代后 的迭代值小于或等于迭代最大值， 否则， 迭代后的迭代值大于迭代最大值。
若 S2等于 0, 说明当前没有发生沖撞， 将 Xi清零， 然后执行步驟 404。 步驟 404、 估算标签总数， 并根据所述标签总数获取最佳 Q值。
所述估算标签总数， 也就是参与通信的标签总数包括： 读取当前帧时 隙数量 Ns ,根据吞吐量计算公式可以得知，在 Ns与标签总数相同的情况下， 系统可达到最大的吞吐量， 因此， 标签总数即为当前帧时隙数量， 根据标 签总数， 读取标签总数与最佳 Q值的映射关系表， 获取标签总数对应的最 佳 Q值， 将当前的 Q值设置为获取的最佳 Q值， 即可获取最大吞吐量， 从 而使得当前阅读器的能耗最低。 所述标签总数与最佳 Q值的映射关系表可 根据经验测量获取， 如图 5所示， 阅读器与标签的传输速率为 lOkbp时， 标签总数与最佳 Q值的映射关系； 所述吞吐量为阅读器成功阅读标签的概 率， 根据吞吐量计算公式：
Throughtput=S1/(S0*T0+S1 *Tl+S2*T2)—- 公 式 (2) , 然 后 根 据 S0 =N (X-\ /Ns --公式 （3) , --公式（4) ,
S2=Ns-So-S! -—公式 (5) , 将公式 (3)、 公式 (4)、 公式 (5)以及公式 (1) , 带入公 式 (2) , 同时使 NS=NT, 即可获取最大吞吐量， 其中， 所述 T0、 T1以及 Τ2 分别为空闲时隙长度、 成功时隙长度以及沖突时隙长度， 可以通过测量获 取。
根据实际测量的结果可以得知， 当功率电平达到一定数值后， 标签的 响应速率保持在 100% ,如图 6所述的标签响应速率与功率电平映射关系表， 所述标签响应速率与功率电平映射关系可根据经验获取， 其中， 当功率电 平达到临界点， 如图 6中的 17 dBm, 标签的响应速率为 100% , 再提高功 率电平， 标签的响应速率保持不变， 对于阅读器的能量是一种浪费， 根据 测量结果可知， 阅读器的功率电平在临界点时， 系统的吞吐量为最大， 因 此， 可以看出， 本发明的方案， 获取最佳 Q值， 使系统达到最大吞吐量， 并使系统保持吞吐量最大时的功率电平， 可以使阅读器的能耗达到最低。
对于沖突时隙、 成功时隙以及空闲时隙的描述如图 7所示， 假设系统 中有 5个标签， 阅读器向标签发出命令， 5个标签接收到命令后都以反向散 射波的形式回复阅读器的询问。 由于标签的回复是随机的， 可以选择在任 何时隙做出回应， 所以不同的标签有可能在同一时隙回复阅读器的询问， 这样会造成沖撞， 此时的时隙就是沖突时隙， 如图中的 TS0、 TS2、 TS4、 TS6。 标签在沖突时隙回复阅读器的询问， 由于发送了沖撞， 阅读器无法正 确阅读标签， 标签无法被阅读器识别。 没有被阅读器识别的标签会不断地 选择新的时隙回复阅读器的询问， 若某一时刻， 在一个时隙中只有一个标 签做出回应， 那么就能成功回复阅读器的询问， 该时隙就是成功时隙， 如 图中的 TS1、 TS5、 TS7、 TS8、 TS9。 被阅读器识别的标签就暂时处于休眠 状态， 不会再抢占时隙。 同时， 也有可能同一个时隙没有任何标签回复阅 读器的响应， 那么这个时隙就是空闲时隙， 如图中的 TS3。
基于以上方法， 本发明还提供了一种提高阅读器能效性能的装置， 如 图 8所示， 该装置包括： 初始化模块 801、 调整模块 802、 设置模块 803以 及估算模块 804;
初始化模块 801 , 用于初始化运算参数， 在初始化完成后通知调整模块 802; 所述初始化运算参数包括： 将调整模块 802中的当前功率电平 P设置 为 P=Pmin-0.5 , 将 Q初始化为 1 , 将设置模块 803中的 初始化为 0;
调整模块 802, 用于调整运算参数， 获取当前帧时隙数量， 确定当前功 率电平小于或等于功率电平最大值， 通知设置模块 803 , 否则， 使当前功率 电平为最大功率电平， 通知估算模块 804; 所述调整运算参数包括： 将当前 功率电平增加递增值， 将当前 Q值加 1 ; 所述通知中包含当前帧时隙数量； 设置模块 803 , 用于更新帧时隙状态， 根据帧时隙状态， 确定需要增加 功率电平， 通知调整模块 802; 确定不需要增加功率电平， 将当前帧时隙数 量发送给估算模块 804;
估算模块 804, 用于根据帧时隙数量估算标签总数， 并根据标签总数获 取最佳 Q值， 将当前 Q值设置为最佳 Q值。
所述设置模块 803 具体用于， 读取当前帧时隙数量， 然后根据帧时隙 数量以及阅读器与标签的通信协议， 更新空闲时隙数、 成功时隙数以及沖 撞时隙数； 所述根据帧时隙数量以及阅读器与标签的通信协议包括： 阅读 器接收标签的回复， 根据通信协议， 若标签回复的代码中， 包含回复失败 信息， 说明标签之间有沖撞， 则接收的包含失败信息的回复的个数， 即为 沖突时隙数； 同样的， 接收的包含成功信息的回复的个数， 即为成功时隙 数； 根据获取的当前帧时隙数量， 以及沖突时隙数、 成功时隙数， 即可获 取空闲时隙数。
所述设置模块 803具体用于：沖突时隙数为 0,或者沖突时隙数大于 0, 且成功时隙数为 0时， 确定迭代后的迭代值大于迭代最大值， 则确定不需 要增加功率电平；
沖突时隙数大于 0, 且成功时隙数大于 0, 或者， 沖突时隙数大于 0, 且成功时隙数为 0时， 确定迭代后的迭代值小于或等于迭代最大值， 则确 定需要增加功率电平。
所述估算模块 804具体用于， 将当前帧时隙数量等于标签总数， 然后 根据标签总数与最佳 Q值的映射关系表， 获取与所述标签总数对应的最佳 Q值， 并将调整模块中的 Q值， 设置为最佳 Q值。
以上所述， 仅为本发明的较佳实施例而已， 并非用于限定本发明的保 护范围， 凡在本发明的精神和原则之内所作的任何修改、 等同替换和改进 等， 均应包含在本发明的保护范围之内。

Claims

权利要求书
1、 一种提高阅读器能效性能的方法， 其特征在于， 包括：
初始化并调整运算参数， 获取当前帧时隙数量；
更新帧时隙状态， 并根据更新的帧时隙状态， 确定不需要增加功率电 平；
根据当前帧时隙数量估算标签数量， 并根据标签数量获取最佳 Q值。
2、 根据权利要求 1所述的方法， 其特征在于， 所述初始化并调整运算 参数， 获取当前帧时隙数量包括：
初始化运算参数， 并将运算参数中的当前功率电平增加递增值， 将 Q 加 1 , 根据当前 Q值及帧时隙数量计算公式获取当前帧时隙数量。
3、 根据权利要求 1或 2所述的方法， 其特征在于， 所述更新帧时隙状 态之前， 该方法进一步包括：
确定当前功率小于或等于功率最大值， 更新帧时隙状态； 否则， 根据 当前帧时隙数量， 估算标签数量。
4、 根据权利要求 3所述的方法， 其特征在于， 所述更新帧时隙状态包 括：
根据当前帧时隙数量以及阅读器与标签的通信协议， 更新空闲时隙数、 成功时隙数以及沖突时隙数。
5、 根据权利要求 4所述的方法， 其特征在于， 所述根据更新的帧时隙 状态， 确定不需要增加功率电平包括：
沖突时隙数等于 0, 或沖突时隙数大于 0且成功时隙数等于 0时， 迭代 后的迭代值大于迭代最大值， 则确定不需要增加功率电平。
6、 根据权利要求 4所述的方法， 其特征在于， 所述根据当前帧时隙数 量估算标签数量， 并根据标签数量获取最佳 Q值包括：
使当前帧时隙数量与标签总数相等， 然后根据标签总数与最佳 Q值的 映射关系表， 获取所述标签总数对应的最佳 Q值， 然后设置当前的 Q值为 最佳 Q值。
7、 一种提高阅读器能效性能的装置， 其特征在于， 包括： 初始化模块、 调整模块、 设置模块以及估算模块；
初始化模块， 用于初始化运算参数， 并通知调整模块；
调整模块， 用于调整运算参数， 获取当前帧时隙数量， 并通知设置模 块；
设置模块， 用于更新帧时隙状态， 根据帧时隙状态确定不需要增加功 率电平， 将当前帧时隙数量发送给估算模块； 所述通知中包含当前帧时隙 数量；
估算模块， 用于根据帧时隙数量估算标签数量， 并根据标签数量获取 最佳 Q值。
8、 根据权利要求 7所述的装置， 其特征在于，
所述初始化模块具体用于， 初始化调整模块以及设置模块中的运算参 数；
所述调整模块具体用于， 将运算参数中的当前功率电平增加递增值， 将 Q加 1 , 然后根据当前 Q值以及帧时隙数量计算公式获取当前帧时隙数 量。
9、 根据权利要求 7或 8所述的装置， 其特征在于，
所述调整模块进一步用于， 将当前功率电平增加递增值， 确定当前功 率电平小于或等于功率电平最大值， 将当前帧时隙数量发送给设置模块， 否则， 将当前帧时隙数量发送给估算模块。
10、 根据权利要求 9所述的装置， 其特征在于，
所述设置模块具体用于， 根据接收的当前帧时隙数量以及阅读器与标 签的通信协议， 更新空闲时隙数、 成功时隙数以及沖撞时隙数。
11、 根据权利要求 10所述的装置， 其特征在于，
所述设置模块具体用于， 沖突时隙数为 0, 或者沖突时隙数大于 0, 且 成功时隙数为 0时， 确定迭代后的迭代值大于迭代最大值， 则确定不需要 增加功率电平。
12、 根据权利要求 7、 8、 10或 11所述的装置， 其特征在于， 所述估算模块具体用于， 将当前帧时隙数量等于标签总数， 然后根据 标签总数与最佳 Q值的映射关系表,获取与所述标签总数对应的最佳 Q值， 并将调整模块中的 Q值， 设置为最佳 Q值。
PCT/CN2011/078851 2011-03-08 2011-08-24 一种提高阅读器能效性能的方法及装置 WO2012119413A1 (zh)

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