TWI220606B - Power control apparatus for achieving respective desired signal quality levels in wireless communication systems and method - Google Patents

Abstract

An apparatus and method is provided for controlling transmission power levels of respective mobile stations in a wireless cellular system, wherein the signal is transmitted from a transmitter at a controlled power level so that either the average received power level or the average signal to interference ratio (SIR) at receiver is close to a desired level. According to a first embodiment, the desired level for the average received signal power is calculated based on the ensemble average intercell interference power level and the desired SIR. According to a second embodiment, the received average SIR is estimated based on the average desired signal power and the ensemble average interference power. The average received power level (average SIR) is compared to the desired level to generate a power control command. The power control command is fed back to the mobile station to instruct the adjustment of transmission power of the mobile station.

Description

1220606 发明 Description of the invention (The description of the invention should state: the technical field, prior art, content, embodiments, and drawings of the invention are briefly explained.) [Technical field to which the invention belongs] The present invention relates to a wireless communication system ( The invention relates to a power control device and method for wireless eommumcation system, and more particularly, to a device and method for controlling the transmission power of each signal transmitting end so that the quality of each received signal reaches a preset desired level. [Prior technology] The known cellular radio telephone system (Ceiiuar telephone system) or personal communication system (Personal Communication System; PCS) refers to a certain number of summer mobile stations (Mobile stations) through the base station (B ase station ) For signal transmission. In the cellular radiotelephone system, there are still many unresolved issues', and power control (PC) is one of the power control schemes of the cellular radiotelephone system with three purposes. 1. Solve the near-far problem. The near-far problem is generally handled by an open-loop or outer-loop power control mechanism. 2. Overcome the effects of Short-term fading 'Multi-path fading' to reduce the fluctuation of the received signal power or signal to interference ratio 6 1220606 (Signal to interference ration; SIR), and get Smoother signal reception quality. The short-range attenuation effect is compensated by a closed-loop, or internal-loop (imier-100p) power control mechanism. 3. Transmission power saving, so that the battery has a longer use time and achieves the purpose of saving power. This part is related to the received power threshold in the power control mechanism or the received signal-to-interference ratio. The critical SIR threshold parameter is related. Generally, if the threshold is adjusted higher, the power consumption of the transmitting end will increase. When a mobile station moves, affected by the characteristics of the transmission channel, the transmission signal will experience the effect of multi-path fading. See U.S. Patent No. 5,056,109, the title of which is "Transmission power control device and method for mobile cellular telephone system with multi-code multiplex access" (METHOD AND APPARATUS FOR CONTROLING TRANSMISSION POWER IN A CDMA MOBILE CELLUAR TELEPHONE SYSTEM), reveals a method for controlling the transmission power of a mobile station to overcome multipath fading. If a mobile station transmits excessive signals, other mobile stations will be interfered by the excessive signals transmitted by the mobile station. However, if the mobile station transmits excessive signals, If the signal is too weak, the base station will not be able to effectively receive the transmission signal transmitted from the mobile station. As in the aforementioned US patent case, the base station transmits the power control command through a separate channel after measuring the power of the received signal. To the mobile station. After the mobile station receives the transmission power command, the mobile station adjusts the transmission power to increase or decrease according to the received transmission power command, so that the average reception power value at the receiving end can be maintained at a preset threshold. Near the value. Such power adjustment actions must be performed periodically 'such as In order to respond to the changes in each environment caused by the movement of each mobile station, the average reception signal level of each communication link at the base station can reach the desired threshold. The closed-circuit power control mechanism can be divided into different methods Strength-based power contol scheme and SIR-based power control scheme. Among them, the closed-loop power control mechanism of this type can be found in US Patent No. 5,257,283, the title of which is "SPREAD SPECTRUM TRANSMITTER POWER CONTROL METHOD AND SYSTEM" and US Patent No. 5,267,262, and its title is "TRANSMITTER POWER CONTROL SYSTEM" However, in these US patents, the threshold value of the received power in the power control mechanism is a preset fixed value, and it does not involve how to adjust the desired received power threshold. To achieve the desired quality of the communication signal.

Also, see US Patent No. 5,216,692, entitled "METHOD AND APPARATUS FOR ADJUSTING A POWER CONTROL THRESHOLD IN A COMMUNICATION SYSTEMS" and US Patent No. 5,396,516 , Its title is "METHOD AND SYSTEM FOR THE DYNAMIC MODIFICATION OF 1220606 CONTROL PARAMETERS IN A TRANSMITTER POWER CONTROLSYSTEMS". Among them, the biggest problem that the US patent case must overcome is a step-wise method for adjusting the threshold level of its received power. However, the disadvantage of applying the stepwise method to adjust the received power & S threshold value lies in the setting of the step size. When the step value is set too large, although it has the advantage of rapid adjustment, it does not reach. To fine-tune the effect. When the step value is set too small, although theoretically a better fine adjustment effect can be achieved, it is less able to take into account the requirements for fast adjustment. In addition, the signal-to-interference ratio (SIR) value is widely used as an indicator of signal quality. Compared with the intensity-type power control, which focuses on the received power, the SIR-type power control focuses on the received signal-to-interference ratio, which directly reflects the signal quality. Therefore, the SIR-type power control is considered as a more direct control mechanism, and its The system performance is found to be superior to the simple power-to-interference-to-interference ratio formula, which is an important theoretical basis for designing SIR-type power control mechanisms. Interestingly, there are many different forms of interference-to-interference ratio formulas in the prior art. For example, in the IEEE Transactions on Wireless Communications journal, Vol. 1, No. 1, ρ · 46-55, Jan · 2002, its name is "Optimal power control in interference-limited fading wireless channels with outage-probability specifications, ”Kandukuri and S. Boyd. According to the formula of the interference ratio in this document, the calculation of the ratio of the interference ratio needs to estimate the individual interference signal power. However, in practice, only the overall interference can be measured. The signal power value cannot be used to measure the power of individual interference signals. 9! 22〇6〇6 So 'receive directly the reception quality required to achieve the desired job quality. The second & threshold level' without borrowing The step-by-step adjustment method is a two-pronged approach: the method of thinking. In addition, how to obtain the individual interference ratio value, and the k-value ratio of these signals-SIR type that can be measured and still can truly reflect the signal The power control mechanism is also another way of accessing. All the questions and calls in the above patents and literatures can be properly answered in the present invention and detailed as [Content of the invention] Another purpose of the present invention in the two types of response systems is to describe the power control capture and |-a kind of power control device and its connection calculation,-no stepping method is required after- And it can be level. _Received power critical value of power control occupational shots Another object of the present invention is to provide a method, the power control device and method thereof, and the method of making clothes on the square table, which means the power control. The device is used for parameters that can be measured by each base station itself. The required operating parameters are for achieving this purpose. The present invention provides a method for controlling a communication device. Set the transmission power of each mobile station to 1220606, in which the system is at least one base station and at least one mobile station. According to the first embodiment, the received power required for each received signal on the base station can reach the desired signal quality. The counterfeit level is calculated based on the overall average intercell interference power value and the desired interference ratio expected value of the received signal. Among them, the overall average external cell interference power value and the signal-to-interference ratio of each received signal are parameters that can be measured and obtained by the base station. In particular, when the number of mobile stations is increased or decreased within the jurisdiction of the base station, the reception The power threshold level can be adjusted in real time. For the communication between each mobile station and the base station, a power control command is used to measure the desired signal received from the mobile station through the transmission channel to the base station. The power is generated after comparing with the corresponding received power threshold. Then, the power control command is transmitted back to the mobile station to adjust the transmission power of the mobile station. In this way, the received power level of each mobile station at the base station is controlled to approach the corresponding received power threshold, and the overall average interference ratio of each mobile station at the base station can approach a corresponding, preset The desired value is thus achieved to ensure the quality of each receiving LuiL 5 Tiger. According to the second embodiment, the average received signal-to-interference ratio is estimated based on the measured average required signal power value and the overall average interference power value. This work can be performed by the base station itself. The threshold value of the received-to-interference-to-interference ratio is calculated from the preset received-to-interference-to-interference ratio. A power control command is generated by comparing the average received interference ratio with its threshold value of the touch ratio and then transmitting the control command to the mobile station to perform the operation. 5 weeks. In this way, the level of each received signal-to-interference ratio is controlled to approach 11 1220606, and the level of its signal-to-interference ratio is expected to ensure the quality of each received signal. In order to make the above and other objects, features, and advantages of the present invention more apparent, the following describes the preferred embodiment of the present invention and the accompanying drawings in detail, as follows. [Embodiment] Hereinafter, preferred specific embodiments of the present invention will be specifically described and described in detail with reference to the accompanying drawings. ^ In the CDMA cellular communication system, due to the characteristics of CDMA itself, the size of its system capacity is strongly related to the interference situation between various communication links. The interference situation between each other is serious, which will damage the system capacity. Relatively, Anything that can reduce the transmission power required by mobile stations is equivalent to reducing the interference situation with each other, so that the effect of increasing system capacity can be achieved. According to a first embodiment of the present invention, a power control device and a method thereof are provided to dynamically control a transmission power level of a mobile station. Through the dynamic control of the transmission power of the mobile station, the effect of increasing the system capacity can be obtained. _ Please refer to FIG. 1. FIG. 1 is a preferred embodiment of the present invention, which is applied to the uplink power control of a communication system, so that the received power approaches its critical value, and the overall average interference ratio tends to Near its desired value, while ensuring the quality of the signal. The so-called "uplink" means that the transmission of the signal from the mobile station to the base station is called the uplink. A wireless cellular communication system includes a plurality of communication cells, and each cell is provided with a base station. Each base station has multiple wireless mobile stations in contact with it. The preferred embodiment of the present invention is mainly applied to a CDMA system. However, TDMA, FDMA and other communication systems are also applicable. The communication signal transmitted from the mobile station to the base station is, for example, a CDMA signal with a single band and a spreading bandwidth of '1.25M 1ζ. In order to obtain the advantages of multi-path transmission, the base station uses a RAKE receiver to process the received signals. Please refer to FIG. 1. The power control device includes an antenna 100, a TXRX duplexer 101, a RX RF module 102, a RAKE receiver 104, Ensemble average desired signal power estimator 106, ensemble average received signal power estimator 108, ensemble average intercell interference of external cell interference signals power estimator) 110, threshold calculator 112, average desired signal power ^ estimator 114, comparator 122, power control command generator (power control command generator 124, a signal generator 130, a modulator 132, and a TX RF module 136. In addition, as shown in FIG. 1, the power control device of the present invention β uses a single receiving antenna, but the power control device of the present invention is not limited to a case where it can only be applied to a single reception antenna. The signal received by the antenna 100 at the base station is an integrated signal 13 1220606 (aggregated signal). The integrated signal includes the mobile station signal in the cell, the mobile station signal and noise in other cells. The received signal is transmitted to the sending / receiving divider 101 and the receiving RF module 102 for frequency reduction and filtering. A pair of receivers 104 received and received the 'number' from the receiving RF module 102 and a PN code (Pseudo Noise code) from a PN sequence generator (not shown on the recording page). . The bar-shaped receiver 104, as is familiar with this technology, is used to perform a despreading process, and has the advantages of making full use of multipath. For each uplink, the spreading code # (spreading code) used at the transmitting end is the reverse spreading code (despreading code) required at the receiving end. For different uplinks, the system will assign different spreading codes. Under the elaborate design of the spreading code, the received signal at the base station is restored to the original bandwidth except for the required signal (using the PN code as the spreading code) after the anti-spreading process, including other signals, including The signals of other mobile stations in the cell, the signals of mobile stations in other cells, and noise are still in the state of spread spectrum. Φ The first embodiment of the present invention provides a power control method, which includes estimating the average power of a desired signal, the average average power of the desired signal (ensemble average desired signal power), and the total average power of the received signal (ensemble average received signal) power) 〇 Consumption · The receiver 104 outputs a comprehensive signal, including the desired signal of the target link, intracell interference signal from the other mobile stations in the same cell, The 14 1220606 intercell interference signal from the mobile stations in the other cells and noise signals in other cells. The output result of the rake receiver i04 during the first data symbol duration zM | >] consists of four parts: ZM [k] = rM [k] + I [k] + Is [k] + n [kl (1) where represents the desired signal and fetch] represents the interference signal. Among them, the interference signal includes an intracellular interference signal and an external cell interference signal. / To] is a multipath interference signal, and η [moxibustion] is a noise signal. It is worth noting that / #] and usually [] are much smaller than [], because they are negligible. In addition, for convenience of description, the following symbols are defined: z, mWH4_2 (2) represents the power value of the received signal ZM at the △ time point at the output of the rake receiver 104;

Pr, M ^ HrMm \ 2 (3) represents the power value of the required signal rM at the time point at the output of the rake receiver 104; p ^ nmi2 (4) represents the interference at the time point at the output of the rake receiver 104 Power value of signal J; Λ turtle

Km = v ^ r (ZM [k]) = E (\ ZM [k] \ 2) (5) is the overall variance of the received signal (ensemble variance), which is the overall average of the received signal power (ensemble average) ;

PrM ^ yar (rM [k]) = E (\ rM [k] \ 2) (6) 15 1220606 is the overall variance of the desired signal ~, which is the overall average of the required signal power; and P / = var (7 [/:]) = £ (| / [/:] | 2) (7) is the overall variance of the interference signal /, which is the overall average of the interference signal power. The rake receiver 104 outputs signals to a received signal power estimator 105 and a desired signal power estimator 107 to estimate the received signal power pz, Mw, and the required signal power, respectively. w. The desired signal power estimator _ 107 outputs the estimated value and transmits it to the ensemble average desired signal power estimator 106 of the desired signal, thereby estimating the overall average required signal power. In addition, after the received signal power estimator 105 outputs the signal, it is transmitted to the ensemble average received signal power estimator 108 of the received signal, thereby estimating the overall average received signal power FZ, M. Observe that in a long-range time interval, the long-range time interval is defined as: a time interval in which the long-range attenuation (10ng_tenn fading) changes slowly to be regarded as a fixed value, and the short-range attenuation (sh. The average value of rt_term fading) is equal to the long-range attenuation value. Without loss of generality, the required and received signals are ergodic random processes. Therefore, the overall average signal power is equal to the average signal power on the time axis. There are many methods to estimate the average signal power on the time axis. One method of 16 1220606 is to take a period of time and then calculate the average power of the signal during this period. Another method of counting the average signal power on the time axis is the running average method. The continuous average equation is

PrM ^ * PrM [k-1] + (1-* PM [k] 5 (8) where Θ is a preset parameter, and the preset parameter is generally a value close to 1 but less than 1. Ensemble average intercell interference power estimator 110 of the cell interference signal, to estimate the total average power of the extra cell interference signal. The required signal rM and the perturbation signal I are not statistically related. Therefore, we get: PZM = PrM + Pi, (9) Once obtained? Z, M and watts, M, Λ can be obtained by the following formula: ρ / = Ρζ, Μ-Pr, M, 10) The interference signal includes from Intracellular interference signals from other mobile stations in the same cell and interference signals from cells outside the mobile station in other cells. The fine Φ intracellular interference signal is not statistically related to the extracellular interference signal. Therefore, the overall average intracellular interference power Ψ / plus the overall average external cell interference power ψ. That is equal to the overall average interference power watt. Total average interference power < Calculated from the following formula ^

Pi _Ψ / + Ψο (11) Here, ~ is a system parameter, taking CDMA communication system as an example, 17 1220606%-the spreading gain value of the key up to the target of the system, (processing gain),

A positive real number related to the PN chip waveform and the PN code cross-correlation. As for TDMA and FDMA systems, GM is 1 for each mobile station M. Because in statistics, the desired signals of each relative uplink are not related to each other, therefore, the overall average intracellular interference power is required by the parent-upper key of the cell except the target link Say the sum of the total average power of 5 tigers. Therefore, the overall average intracellular interference power is: —L-· Ψ / = Σ (12) ίη-\, ηιΦΜ L is defined as the number of mobile stations in the cell. Theoretically, the overall average interference power% of each chain in the cell is the same. Through formulas (10), (n), and (12), a formula (13) can be obtained, and thus obtained. W〇 = GMPzM- ~ GMPrM-- Pr, m5. (13) Therefore Ψ. It can be obtained by the power level of the overall average received signal, the power level of the overall average ⑩ desired signal {Km · ^ 2 = 1, ··· ×}, and system parameters. In addition, if the formula (I) corresponding to each M value is considered at the same time, a more accurate% estimation value can be obtained as follows:-^ 〇 = ji \ GMPzM ~ GMPrM- X Pr, X (14)

m-Xnm JV Taking the equation (14) as an example, the power level of the average average received signal is 4 7 ^,] \ / 1 = 1, ... 丄}, 18 1220606 of the average average received signal The power levels {A, μ · M = 1, ···, I ^} and the system parameter Gm {Gm are obtained. A threshold calculator (12) is used to find the critical value of the received power of each uplink in the cell. The threshold calculator 112 · transmits the calculated threshold to the comparator 122. The composition of the threshold value calculator 112 includes a certain number of internal counters, program memory, and data memory. The cutoff value of the critical value a of 10½ is based on the overall average outer cell interference power level and the preset overall average interference ratio value to first obtain the overall average expected value of the received power, and then according to a ratio The critical value is obtained. The threshold calculator can be set at the base station or mobile teiephone switching office. The instantaneous received signal-to-interference ratio at the output of the twisted receiver 104 can be obtained by the following equation ... (15) (16) Γ 「η-丨 ~ [幻 I [众] M var 卿-~ JT · According to the equation (11) and (12), we can get: ^ mW = Gm · —L-, M = 1, ..., L. Σ After calculating the overall average (ensenible average operation) at both ends of the special code (16) , We can get L L-ary linear equation systems, as shown below: 19 1220606 G. Corpse ,, 1-Γΐ · Corpse,, 2-…-· Γΐ Pr, L · ψ〇-Γ2 Pr, l + G? Pr, 2-· * " ~ Γ2 * PrX = p2, ψ; (Π) -ΓL · Pr, \-·-Tl * Pr, L- \ + GL Pr L = f L · ψ〇 where fM = E (rM [k]) Jor M = 19.,. 9l (18)

Is the overall average interference-to-interference ratio of each mobile station M at the base station. Once the expected value of the overall average interference ratio {? M, M = 1, ..., L} is selected and the overall average external cell interference power% is also measured, the L L by formula (17)

The first-order equation system can obtain the expected value of the overall average received power on each communication link {Watt, M = 1, ··· ;;}. When the mobile station is added or removed from the cell, the value of {Α, μ} can be recalculated immediately, so the value of {Κ, Μ} can be adjusted immediately according to the situation. By properly selecting the desired value of h, the desired quality of the signal can be ensured. According to different practical requirements, the signal quality indicator can be the overall average signal-to-interference ratio or the overall average bit error rate (BER) value, where the overall average bit error rate is defined as the overall average of the instantaneous bit error rate. Generally speaking, L is a function of the overall average BER-Li Yi. Once the overall average BER and the relationship curve of the hope are obtained, the h value of the hope can be obtained accordingly. The relationship graph of Walling-h can be obtained by "experimental or theoretical analysis. According to the modulation scheme, the BER-SIR graph and the probability density function of SIR in formula (15) ), You can easily derive a beautiful relationship curve graph. Therefore, to ensure the required quality of the signal, it is equivalent to selecting the desired value of the overall average interference ratio ^ at the appropriate 20 1220606. Finally multiply the tile ▲ by a factor αM That is, a critical value is obtained, where the factor 0 tM is the ratio of the corresponding critical value to the overall average received signal power. Taking a cellular mobile phone system as an example, because the adjustment step of the transmission power is a pair of values, the overall average reception The signal power will be slightly higher than the power control threshold. At this time, αM will be slightly smaller than the value of i. The value of the factor 0 ^ system can be obtained through experimental or theoretical calculation. If it is convenient,

OtM can also be set directly to 1, but the overall average interference ratio obtained in the end will be slightly higher than the preset expectation. The average power estimator 114 of the desired signal is an average value of the required signal power from the desired signal power estimator 107 in a power control period, as shown below 1 Γ Ί, 2 1 ^ 0 + ^-1

PrM Σ Κ WI ΣΡΓ, Μ [ί:] (19) Λ k =: k0 V) where K is the number of data characters covered in a power control period, k is the data character index, and k is the power control period Index of starting data characters. A comparator 122 compares the threshold value output by the threshold calculator 112 with the average power of the desired signal and estimates the average required signal power level of the 114 output. A power control command generator 124 generates a power control command periodically after receiving the comparison result from the comparator 122, and then transmits the power control command to the corresponding mobile station. The power control instruction in the embodiment of the present invention is generally a unified bit instruction. Enumerate n == 1 21 1220606 as an example. ‘Power control} daily command is a power-up instruction and a poWer-down instruction. If the average required signal power is lower than the critical value, the power control indicator 124 generates a Power-up instruction. Conversely, if the average required signal power is higher than the critical value, the power control command generator 124: will generate a power-down command. In the signal generator 13, the power control command from the power control command generator 124 is integrated in a transmission frame, and then sent to the modulator 132. The modulator 132 outputs a transmission signal to the TX RF module 136 for frequency upconversion after modulating the transmission signal, that is, spread spectrum modulation, to obtain a radio frequency signal. The radio frequency number is finally transmitted via a transmitting / receiving duplexer (RX / TX duplex) 101 and an antenna 100. It is worth noting that the parameters required for the device and its method shown in Figure 1 of the first embodiment of the present invention can be measured and estimated at each base station without relying on the overall system level parameters. Please refer to Fig. 2. Fig. 2 is a flow chart of the second embodiment of the present invention, which is to achieve the required signal level required by the chain by power control. In other words, it is said that the mobile station and the base station transmit via a transmission link. The communication device of Brother 2 includes: an antenna 100, a transmitting and receiving division device 101, a receiving radio frequency module 102, a rake receiver 104, a receiving signal power-estimator 105, and a required signal power Estimator 107, a total and volume average power estimator 106 of a desired signal, a total average power estimator 108 of a received signal, a total average interference power estimator 210, an average interference ratio estimator 220, a comparison Generator 222, a power control command generator 124, a signal generator 130, a modulator 132, and a transmitting RF module 136. It is worthwhile to note that the power control device of the present invention uses a single receiving antenna, but it is not necessarily limited to a single receiving antenna. In the second embodiment of the present invention, the antenna 100, the receiving radio frequency module 102, the rake receiver 104, the received signal power estimator 105, the desired signal power estimation module 107, and the overall average power of the desired signal The estimator 106, the overall average power estimator 108 of the received signal, and the average power estimator 114 of the desired signal are the same as those in the first embodiment, and therefore will not be described here. A total average interference power estimator 21 is used to estimate the total average power of the interference signal. In general, the desired signal Γμ has no statistical correlation with the interference signal I. Therefore, there are the following equations: ^ ΡΓΜ + 普, (20) where the value and value are the output values of the total average power estimator 108 of the received signal and the total average power estimator 106 of the desired signal, respectively. Therefore, once you get the value of ^^ and: ^^, you can get the overall average interference power.

Pi —PZ, M — Pr, M. (21) Consider observing in a long-range time interval. Here the so-called long-range time interval is antisense: within this time interval, the change of long-range attenuation (10ng_term fading) slowly reverses to It can be regarded as a fixed value, and the average value of short-term fading is equal to the long-term fading value. Both the desired signal and the received signal will be ergodic random processes, so we can know the overall average. δίΐ 7 Tiger power is equal to the average signal power on the time axis. There are many methods to estimate the average signal power on the time axis. One of 23 1220606 is to take a period of time and then calculate the average power of the signal during this period. Another method of counting the average signal power on the time axis is the running average method. Generally speaking, both the first and second embodiments of the present invention use this method to estimate the average signal power on the time axis. A desired signal average power estimator 114 is used to average the desired signal power during a power control period. For example, the average required signal power: can be obtained from equation (19). The average sfl interference meter 220 ′ estimates the average signal ratio of the signal according to the average required signal power value I and the overall average interference power watt value. More specifically, the average interference ratio r Μ value can be obtained by the following formula: ΓΜ =

(twenty two)

In particular, the derivation of the formula of the rM value of the average interference ratio is based on the starting point of derivation in the long-range time interval. In this long-range time interval, long-term fading can be regarded as a time-constant; that is, the local mean of the channel gain. Short-term fading is an ergodic random processes. Therefore, the overall channel benefit—the product of long-range and short-range attenuation—becomes a stationary random process. In addition, assuming that under the power control mechanism, the transmission power can also be regarded as a 24 1220606 steady-state random program. In this way, when observed within this long-range time interval, the instantaneous received signal interference ratio is equal to the instantaneous received signal power value divided by the overall average interference signal power value. The average signal-to-interference ratio is equal to the average received signal power value divided by the overall average interference signal power value. Since the calculation of the interference-to-interference ratio of the present invention is a theoretical basis derived from observation in the long-range time interval, the calculation method of the interference-to-interference ratio disclosed in the embodiment of the present invention is different from other conventional technologies. For example, in the IEEE Transactions on Wireless Communications journal, Vol. 1, No. 1, pp. 46-55, Jan. 2002, its name is "Optimal power control in _ interference-limited fading wireless channels with outage-probability specifications &quot; S. Kandukuri and S. Boyd. In this document, the signal-to-interference ratio is defined as the ratio of the desired signal power divided by the sum of the individual interference signal powers. The calculation of the signal-to-interference ratio requires the sum of the individual interference signal powers, however In fact, it is not easy to obtain the sum of the power of individual interference signals. The reason is that when discussing from the point of view of signal vector space, 'Each individual interference disorder corresponds to a vector. The overall interference signal is Is the sum of the vectors. The power of the overall interference signal is the absolute square of the sum vector. It is measurable. However, it is impossible to infer from the sum vector to obtain the contained sub-vectors. , So it is not possible to derive the value of the power of individual interference signals, so the denominator part of the interference ratio formula is only The meaning of analysis' is not practical in practice. Any power control device that uses the formula of the interference ratio is not practical. In contrast, the denominator part of the formula of the interference ratio in the present invention is measurable 25 1220606 In a long-range time interval, the Taxogan Alum is a steady-state, ergodic random program. Ab_ is active or the interference signal is a quasi-stable process. , But in a long-range time interval, it can be regarded as a -steady-state, ergodic random program .: The equation of the interference ratio in Equation (22) can be used in any system to estimate the average value of the time interval Interference ratio ... All received signals, desired signals, and interference signals within the interval of the Changhong day can be regarded as a steady-state random program, and the length of the long-range time interval is longer than the coherence time of the procedures that violate these procedures. c〇herent time) w is longer. At this point, the coherence time bound according to the random program s⑴ is a real number, so that for any time point that satisfies | tKt2 | <W s (t2) has a statistically significant correlation. After an average value on a time axis is calculated in such a long-range time interval, it is taken as its overall average value. In addition, the continuous average method can also be used to obtain the overall average value. A comparator 222 ′ is used to compare the average disturbance. The average signal-to-interference ratio from the ratio estimator 22 and the overall average signal-to-interference ratio preset for the on-chain _ hope value. The power control command generator 124 periodically compares the results of the comparison with the comparator 222, and generates a power control command periodically and transmits it to its corresponding mobile station. The power control instruction in the embodiment of the present invention generally generates an n_-bit sum order. Take n = l as an example. The power control instruction is a power-up instruction and a power-down instruction. If the average interference-to-interference ratio is lower than the expected interference-to-interference ratio, the power control command generator 124 generates a power-up command. Conversely, if the average interference ratio value is higher than the expected interference ratio value, the power control instruction generator 124 generates a power-down instruction. In the signal generator 26 1220606 130, the power control instruction transmitted from the 'power control instruction generator 124 is rectified &amp; in the transmission frame, and then sent to the modulator 132. In the second embodiment of the present invention, the signal generator 130, the modulator 132, the transmitting RF module 136, and the transmitting / receiving division unit ι01 are the same as the first embodiment. It is worth noting that the parameters required for the device and its method shown in Figure 2 of the second embodiment of the present invention are all parameters that can be estimated by each base station without relying on the parameters of the overall system level.凊 Refination A ?, Brother 3? The third figure is a simulation result of a failure probability versus the number of mobile stations per cell. The probability of failure is defined as the probability that the received signal-to-interference ratio level is lower than a preset signal-to-interference ratio level, and the system transmission capacity is defined as the maximum value of the mobile station in each cell; approximately 1% outside Chance. The simulated wireless system consists of 37 bee-like cells. The channel propagation index (pr0pagation exponent) is 3.5. In multi-path channel mode (multi_path channel mode), the number of paths is two. The spread-spectrum gain is 128. The expected value of the interference-to-interference ratio is 6.67dB, which is the required signal-to-interference ratio in the BPSK modulation method to obtain BER =: 1〇-3. Rayleigh fading random processes are generated by a jake model that is well known to those skilled in the art. Long-range attenuation is randomly generated according to the channel model, and the positions of the mobile stations are evenly distributed in the system. In addition, the graph in Figure 3 is generated according to the following preset values: the mobile speed of each mobile station is 20 km / hr, and the power control step value (p〇wer adaptati〇n £) is ldB The power control cycle is 2/3 ms and the power control loop delay is a power control cycle. 27 1220606

The upper line 302 is an A-Wenxi line of the embodiment of the present invention, and the curved line 304 is an intensity-type power control machine of traditional conventional technology ▲: The old, dead, and knot 06 are SIR of traditional conventional technology Type of work: energy curve. Among them, the conventional type of strong power control mechanism is used to control the transmission power of each mobile station in the system so that the receiving power at the receiving end approaches the preset level. The other type of traditional power control mechanism is used to control the transmission power of each mobile station in the system, so that the receiver interference ratio at the receiving end approaches a preset level. The ratio of the received random power divided by the average interference power. As shown in Figure 3, taking the probability of failure as an example, the present invention can obtain a higher system capacity than the transmission-intensity-type and SIR-type power control mechanisms. … In addition, according to the power control method of the embodiment of the present invention, a CDMA spread spectrum signal is connected to a frequency modulator, an antenna, and a demodulator through a wireless transmission link. The interference signal may also be a noise interference signal and the transmission link may be an electronic data bus, a general transmission line, an optical fiber line, and other types of transmission links. The power control method of the present invention is also applicable to other wireless communication systems, such as TDMA and FDMA communication systems. As will be understood by those familiar with this technology, the above descriptions are merely preferred embodiments of the present invention, and are not intended to limit the scope of patent application for the present invention; all others completed without departing from the spirit disclosed by the present invention, etc. Effective changes or modifications should be included in the scope of patent application described below. Although the present invention has been described with reference to its related preferred embodiments, then the reunification 28 1220606 is not intended to limit the present invention. It should be understood that any person skilled in the art should not depart from the spirit and scope of the present invention. Various modifications and changes can be made without departing from the spirit and scope of the patent scope of the present application. The scope of protection of the present invention shall be determined by the scope of the attached patent application. [Brief description of the drawings] The preferred embodiment of the present invention has been described in more detail in the foregoing explanatory text with the following figures, where: _ Figure 1 is the first embodiment of the present invention, the power at the base station System block diagram of control mechanism; FIG. 2 is a system block diagram of a power control mechanism at a base station according to a second embodiment of the present invention; and FIG. 3 is a performance curve simulation diagram of an embodiment of the present invention. 29

Claims (1)

1220606 = Used to reduce the desired signal quality level in the communication system. The wireless communication system includes a plurality of receivers and transmitters, each of which emits power. The signal sent by the power level controlled by the control mechanism, each #g 鐽 ... im h through the individual communication, at the receiver-the device includes at least: the required signal power measurement device for measuring The power level of the desired signal on each communication key;-the received signal power measurement device 'is used to measure the power level of the received signal on each communication link;-the required power statistics acquisition device for ^ is used to The required signal power value measured on each communication link during the day is calculated by an arithmetic expression, and the statistical value of the required signal power is paid out;-the device for receiving the signal power statistics value acquisition device is used to connect each communication key to the The measured received signal power value is calculated by calculating the difference of the received signal's power;-the overall average value of the external cell interference signal is estimated , Based on at least one of the desired signal statistics and at least one of the received signal statistics to estimate the overall average value of the external cell interference signal; and—the receiving power threshold level calculation and adjustment device, based on the external cell interference Λ The overall average number of the number 'the overall average hope ratio of each communication link, calculate the new received power threshold value on each communication link, and adjust the received power threshold on each communication link 30 1220606 value. 2 =: = The device described in item 1, wherein the calculation formula used to calculate the statistic and the calculation formula 1 used to calculate the received signal power are: ❿ Input value 'Calculates these The average value of the input values ... The output value of the transport type 'where the time interval is a long enough interval between the chemistries, so that short-term attenuation can be averaged out. = The device described in item 1 of Shenli Fan 15, in which the calculation formula used to calculate the rate statistic and the calculation formula used to calculate the statistics of the received signal power are: Then perform-different on the input values to get the output value of the expression. The: d · Average signal-to-interference ratio measurement device in the time interval. The door weight F requires the door condition number average power level measurement device to measure the average of the required signal power within the period of time. The interference power level acquisition device is used to obtain-the overall average interference power level; and the average interference power level is calculated to obtain the average information-flat material calculation device, using the readings to establish standards and the overall contractor. Photo ", seven h ^ 31 1220606 interference ratio value. Kizaki ratio measurement device,, and m thousand interference power level acquisition device, including: First: the signal power measurement device to obtain-the desired signal power level ; = ^: Set: == A received signal power measurement device is accurate; used to obtain a received signal power bit received signal statistical value to obtain the device, connected to the seven series will be the received signal power value, after a transport We can calculate the value of 3pvpα; and use the unified overall average interference power of a received signal power after the hard # formula to calculate the M, by subtracting the required signal power statistical value from the received signal power statistical value to Obtain an overall average interference power level. 6. If applying for a full-time measurement of the average signal-to-interference ratio measurement device described in item 5, the calculation formula used to calculate the desired signal power statistics and the calculation formula used to calculate the received signal power statistics are: : Receive the input value within a period of time, calculate this value as the output value of the expression, where the &amp; hour_two == 32 of the desired signal and the time interval of the received signal, so that the number in this time interval Generally can be regarded as a steady-state random process. 7. ::: The average signal-to-interference ratio measuring device described in the patent * 5 item, the calculation formula that differs from the desired signal power statistics and the calculation formula for the statistics of the received signal power are: ί The input values are received in sequence, and then -continuous average difference is performed on these input values to obtain the output value of the operation formula. This type of application is used in a wireless communication system to achieve the desired signal quality and hope for a standard M system. Among them, the 5H wireless communication system includes a plurality of transmitters that receive signals, and each transmitter is controlled by a power control mechanism; Beiting signal 'The signal sent by each transmitter is transmitted to its receiver through a separate communication key. The method includes: · measuring the power level of the desired signal on each communication link; The required signal power value measured on the link is calculated by a different method to obtain the statistics of the required signal power; the power level of the received signal on each communication link is measured; The received signal power value measured on the link is calculated by a j-transport operation to obtain the statistics of the received signal power; based on at least one of the desired signal statistics and at least one of the received signal statistics , To estimate the overall average value of the interference signal of the outer cell; and 33 1220606 based on the overall average value of the interference of the outer cell, the overall average domain ratio of each copper news agency Value, calculating a new registration record on the received power of each of the critical barrel ⑽ junction, according to the received power threshold to the difficulty depends on the respective junction. 9. The method as described in item 8 of the scope of patent application, wherein the calculation formula used to calculate the f signal power statistics and the calculation formula used to calculate the received signal power statistics are: receive-period The input value within the interval is calculated as the average value of these in-turn values. The output value of the "Hyunyun" is calculated, where the time interval is a sufficiently long #interval, so that the short-term attenuation can be averaged out. 10. The method according to item 8 of the scope of patent application, wherein the calculation formula used to calculate the signal power statistics of the institute and the calculation formula of the received signal power statistics are: ㈣ Receive input value Then, perform a continuous average operation on some input values to obtain the output value of the operation formula. • A method to find the average interference-to-interference ratio in a time interval, including: And calculate an average interference-to-interference ratio based on the average power level of the desired signal and the overall average interference power of 34 1220606 levels. 12. The method as described in item 帛 U of the scope of patent application, wherein obtaining the overall average interference power level includes the following steps: measuring a required signal power level; obtaining a statistical value of the required signal power, which will be The measured value of the required signal power is obtained through a different type of operation to obtain the statistical value of the required signal power. Measure a received signal power level. Β Obtain a statistical value of the received signal power. The measured value of the received signal power is obtained through an arithmetic expression to obtain the statistical value of the received signal power; and the statistical value of the received signal power is subtracted from the desired signal power to calculate the overall average interference power level quasi. 13_ The method according to item η of the scope of patent application, wherein the calculation formula used to calculate the required signal power statistics and the calculation formula used to calculate the statistics of the received signal φ power are: The average value of these input values is calculated as the output value of the operation formula, where the time interval is a sufficiently long time interval, so that the desired signal and the received signal in this time interval are generally visible. It is a steady-state random process. 14. The method as described in item u of the scope of patent application, wherein the calculation formula used to calculate the required signal power statistics of 35 1220606 and the nose movement formula used to calculate the statistics of the received signal power are: Receive input values, and then perform a continuous average operation on the input values to obtain the output value of the operation formula. 36