• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Optimal UAV deployment in downlink non-orthogonal multiple access system: a two-user case

    2020-11-27 09:17:14LiuTingting劉婷婷WangYuntianWangJunhuaPanZiyuYuYu
    High Technology Letters 2020年4期
    關(guān)鍵詞:控制率進(jìn)展例數(shù)

    Liu Tingting (劉婷婷), Wang Yuntian, Wang Junhua, Pan Ziyu, Yu Yu

    (*School of Information and Communication Engineering, Nanjing Institute of Technology, Nanjing 211167, P.R.China)(**Nanjing University of Science and Technology, Nanjing 210094, P.R.China)(***Nanjing University of Aeronautics and Astronautics, Nanjing 210024, P.R.China)

    Abstract

    Key words: unmanned aerial vehicle (UAV) deployment, downlink non-orthogonal multiple access (NOMA), two-user case

    0 Introduction

    Recently, non-orthogonal multiple access (NOMA), which is recognized with high spectrum efficiency, has attracted great attention as a crucial technique for 5G networks[1-3]. Employing the NOMA scheme, users can be multiplexed at different power levels, while users can simultaneously access other resources, such as frequency, time or code resources. At the receiver side, users utilize a successive interference cancellation (SIC) to extract their corresponding signals[4].

    Although, NOMA can achieve superior performance, edge users in a network still suffer from service quality degradation. There are still many challenges to advance NOMA in 5G networks. For these reasons, because of the flexibility for deployment, unmanned aerial vehicles (UAVs) or drones with advanced sensors and transceivers have attracted great attentions in communication community. Specifically, UAVs can exploit the benefits of line-of-sight (LoS) air-to-ground communication channels to provide enhanced communication services, such as mobile coverage[5,6], mobile relaying[7,8]and mobile data collection[9-11], etc.

    Existing researches on UAVs can be divided into 2 directions, i.e., static-UAV and mobile-UAV directions[12]. The combination researches on the mobile-UAV and NOMA scheme focus on the UAV trajectory design and communication scheduling. In Ref.[13], the authors optimize the trajectory of UAV and the precoding vectors of NOMA base station (BS) in order to maximize the sum rate for UAV-assisted NOMA networks.

    In order to enhance the service quality for multiple users, the combination researches on the static-UAV NOMA scenario are also promising. In Ref.[14], the authors derive the outage probability of UAV connected users and device-to-device (D2D) underlaying NOMA static-UAV assisted networks, and provide a sub-optimal power control solution. Besides the outage probability, UAV’s placement problem in a static-UAV NOMA scenario is also very important, especially for enhancing the service performance of edge users. In Ref.[15], the authors investigate the UAV placement and power allocation problem. The problem is separated into 2 sub-problems. The optimal location of UAV is obtained by minimizing the sum path loss, and the optimal power allocation is then derived.

    Different from the existing work, this paper investigates the optimal UAV deployment problem in downlink NOMA system from the perspective of maximizing user’s sum rate. The main contributions of this paper are listed as follows.

    (1) A UAV-enabled NOMA system, where a UAV is deployed as an aerial base station, which transmits data to two ground users, is considered in this paper.

    (2) In order to maximize two users’ achievable sum rate, an optimal UAV placement problem is therefore constructed. Since it is intractable to solve this problem, a feasible solution region is first reduced by a theorem. Then, an analytical solution of the proposed problem under a certain situation is discussed.

    (3) Finally, an algorithm is proposed to solve the optimization problem in a general manner.

    (4) Extensive numerical results are presented to demonstrate effectiveness of the proposed algorithm, and its advantages over the benchmarks from the perspective of maximizing users’ sum rate.

    This paper is organized as follows. System model and problem formation are presented in Section 1. The proposed algorithm is elaborated in Section 2. Extensive numerical results are depicted in Section 3, and finally conclusions are drawn in Section 4.

    1 System model and problem formulation

    As shown in Fig.1, a UAV-enabled NOMA system, where a UAV is deployed as an aerial base station to transmit data to two ground users, is considered in this paper. Without loss of generality, a 3-D Cartesian coordinate system is considered with two ground users, i.e., user 1 and user 2 in Fig.1, located atw1=[L, 0, 0]Tandw2=[-L, 0, 0]T, respectively. It is assumed that the UAV is deployed atq=[x,y,H]T, whereHis the fixed flight altitude of the UAV. For simplicity, it is assumed that all the nodes in the network are equipped with a single antenna, and the communication links from the UAV to the ground users are line-of-sight (LoS) dominated. It is also assumed that the Doppler effect caused by the UAV motion is perfectly compensated at the ground users. Thus, the channel coefficienthifrom the UAV to useri, {i=1,2}, can be expressed as

    (1)

    where,λ0is the channel gain at the reference distanced0=1 m, anddi=|q-wi| denotes the distance from the UAV to useri.

    Fig.1 UAV-enabled NOMA network with two users

    The UAV transmits the superposition signal to the two ground users simultaneously, which can be expressed as

    (2)

    wheres1ands2denote the signal intended for user 1 and user 2, respectively.P1andP2are the corresponding transmission power for user 1 and user 2, respectively. The transmission power must comply with the following 2 conditions.

    P1+P2≤Pmax

    (3a)

    Pi≥0,i=1,2

    (3b)

    wherePmaxdenotes the maximum transmission power of the UAV. Thus, the received signal at useriis

    i=1,2 (4)

    According to NOMA principle, SIC is utilized at the receivers. Because of symmetry, only the case withx≥0 is considered in the following discussions. Also it is assumed that user 1 is treated as a stronger user, while user 2 is treated as a poorer user. Thus, the signal intended for user 2 is first decoded, and then for user 1. As a result, the achievable rate from the UAV to user 1 and user 2 can be expressed as

    R1=log2(1+P1λ1)

    (5a)

    and

    (5b)

    In order to maximize users’ achievable sum rate, an optimization problem can be formulated as

    (6a)

    s.t., Eq.(3a), Eq.(3b)

    (6b)

    Ri≥r*,i=1,2

    (6c)

    whereP={P1,P2}, andr*denotes the achievable rate threshold. Constraint Eq.(6c) can be used to guarantee user’s quality of service (QoS). It can be seen that problem Eq.(6) is non-convex. Because the objective function Eq.(6a) is non-concave, and the constraint Eq.(6c) is non-convex with respect toqandP, respectively. Thus, it is challenging to solve problem Eq.(6) by the conventional optimization methods.

    2 Proposed algorithm for problem Eq.(6)

    In this section, the solution of problem Eq.(6) will be provided. First, the problem is simplified. Then, an analytical solution of the simplified problem under a certain situation will be presented. At last, a generalized algorithm is proposed to obtain the optimal solution of problem Eq.(6).

    2.1 Problem simplification

    In order to simplify problem Eq.(6), Theorem 1 is provided as follows.

    Theorem1To maximize users’ summation of the achievable rates, the UAV should be deployed above the line segment between the two users.

    ProofTheorem 1 is demonstrated by contradiction. This work first assumes that the optimal UAV deployment location is given byq0=[x0,y0,H]T, wherey0≠0. That is to say, the UAV is not located over the line through the two users. The UAV transmits with the maximum transmission power at the optimal solution[16], i.e.,

    P1+P2=Pmax

    近期療效評(píng)價(jià)[3]:完全緩解(CR)指肺癌病灶完全消失,無(wú)新起病灶,且時(shí)間持續(xù)1個(gè)月以上;部分緩解(PR)指肺癌病灶面積縮小程度>50%以上,無(wú)新起病灶;病情穩(wěn)定(SD)指肺癌病灶面積縮小程度≤50%,增大程度≤25%;病情進(jìn)展(PD)指肺癌病灶面積增大程度>25%,或有新起病灶。疾病控制率(DCR)為(CR+PR+SD)/總例數(shù)。

    (7)

    Then, the achievable rates of the two users at the optimal solution can be expressed as

    (8a)

    and

    Conditions Eqs(8a) and (8b) are satisfied because of the QoS constraints. Given another UAV’s location atq1=[x0, 0,H]T, that is to say, the UAV’s location is over the line of the two users, i.e.,

    (9)

    (10a)

    (10b)

    where condition Eq.(6c) in Eq.(10b) holds, since ifα>β, the functiong(x)=log2(1+αx)-log2(1+βx) is monotonically increasing with respect to the variablex. Therefore, the sum rate atq1=[x0, 0,H]Tis larger than that atq0=[x0,y0,H]T, ?y0≠0. This conclusion contradicts the assumption thatq0is the optimal location that can get the maximum sum rate. Therefore, it can be concluded that a higher sum rate can be achieved by deploying the UAV over the line through the two users compared to other locations.

    Next, proofs on that the optimal UAV location should over the line segment between the two users are provided. Given a locationq2=[x, 0,H]T, ifx>L, i.e., over the extension line of the two users, the UAV can be always deployed atq3=[L-(x-L), 0,H]Twhich is a symmetrical location respective to user 1, and obtain a larger sum rate compared to that atq2. As a result, in order to maximize the sum rate of the two users, the UAV should be deployed above the line segment between the two users, i.e., 0≤x≤L. This completes the proof.

    Based on Theorem 1, the UAV’s location can be simplified asq=[x, 0,H]T. According to the conclusion drawn in Ref.[16], in order to obtain the maximum sum rate, the optimal power allocation strategy can be represented as

    (11a)

    and

    (11b)

    (12)

    and

    R2=r*

    (13)

    respectively. Observing Eqs(12) and (13), it can be found that by employing the power allocation strategy, the rate of user 2, i,e, the poorer user, is equal to the rate threshold and irrelevant to the UAV’s location. The rate of user 1 can be further enhanced by varying the UAV’s locationx.

    Thus, problem Eq.(6) can be simplified as

    maxxf(x)

    (14a)

    0≤x≤L

    (14b)

    where

    (15)

    In order to assure rate of the user 1 is larger than the rate thresholdr*, the following remark is provided.

    Remark1If the maximum value off(x) is greater than 2r*(2r*-1), problem Eq.(6) is feasible. Otherwise, problem Eq.(6) is infeasible and a smaller value ofr*should be considered.

    When problem Eq.(6) is feasible, the following remark is provided.

    Remark2The sum rate of the two users, i.e.,R1+R2, is decreasing asr*increases.

    ProofThe first-order derivation ofR1+R2is as follows.

    (16)

    Since 0≤x≤L, thusλ1>λ2holds. Moreover, based on Remark 1, Eq.(16)<0. Thus,R1+R2is an decreasing function respective tor*.

    Note that problem Eq.(14) is a univariate optimization problem which may be solved by derivation.

    2.2 The analytical solution to problem Eq.(14)

    The first-order derivation off(x) is given by

    (17)

    2Lx2-Ax+AL-2L(H2+L2)=0

    (18)

    Eq.(18) is a quadratic function withΔ=A2-8AL2+16L2(H2+L2). IfΔ≥0, then the stationary points off′(x) are given by

    (19)

    In the following, it should be determined whether the 2 stationary points are in the interval, and then obtain the optimalx(denoted byx*). Based on the above derivations, the UAV deployment strategy is concluded in Algorithm 1.

    Algorithm 1Proposed UAV deployment strategy1.IfΔ≥0then2.Case 1Ifx1Solu∈(0, L), x2Solu∈(0, L),thenx*=argmax{f(0), f(x1Solu), f(x2Solu), f(L)}3.Case 2Ifx1Solu∈(0, L), x2Solu?(0, L),thenx*=argmax{f(0), f(x1Solu), f(L)}4.Case 3Ifx1Solu?(0, L), x2Solu∈(0, L),thenx*=argmax{f(0), f(x2Solu), f(L)}5.Case 4Ifx1Solu?(0, L), x2Solu?(0,L),thenx*=argmax{f(0), f(L)}6.Elsef(x) is a monotonic increasing function with respect to x. Therefore, x*=L7.End if8.If f(x*)≥2r*(2r*-1)thenx* is determined.9.Else10.Reconsiderr*.11.End if

    Note that the proposed algorithm is applicable in a two-user scenario. For the multi-user scenario, the optimal UAV deployment problem is complex, and it probably cannot get a closed-form solution. The UAV deployment problem will be investigated in a multi-user scenario in the future work.

    3 Numerical results

    In this section, numerical results are presented to demonstrate effectiveness of the proposed UAV deployment scheme (denoted as the DP scheme). The simulation parameters are set asL=500 m,Pmax=1 W,H=100 m, andγ0=106.

    Fig.2 plots the optimal UAV deployment location using the proposed DP scheme whenr*varies. Linear search curves are also plotted to verify the correctness of the analytical solution. It is clearly presented that the linear search results are well matched with the analytical results. It can also be observed that the optimal UAV deployment location moves away from user 1 asr*increases. The reason is that asr*increases, user 2 needs more transmission power to satisfy the QoS constraint, and, therefore, the UAV tries to strike a balance between the transmission power of the two users. This phenomenon can be also verified by Remark 2.

    Fig.2 Optimal deployment location for DP scheme versus r*.

    For comparison, the following 2 schemes are considered as benchmarks.

    (1)FDMAA UAV-enabled FDMA system, which is different from NOMA system in this paper, also can demonstrate that the optimal UAV deployment location is over the line segment between the two users. Given a UAV’s location and the power constraint, in order to maximize the sum rate, the optimal power allocation based on the water-filling scheme is first determined. Then, the location is varied to find the optimal solution that can maximize the sum rate. This scheme can be used to demonstrate advantages of the NOMA system.

    (2)PoweroptimizationwithoutUAVdeployment(POWD)A UAV-enabled NOMA system, where the UAV’s location is fixed over user 1 and the optimal transmission power is obtained with the same manner used in our scheme. POWD scheme is used to demonstrate the advantages of the DP scheme.

    Fig.3 plots the variation of sum rate for the FDMA scheme versus differentr*. A curve of NOMA whenr*=0.8 is also plotted for comparison. A portion of the FDMA scheme curves are not drawn, due to the reason that the QoS constraint is not satisfied. Moreover, the NOMA scheme can always achieve a higher sum rate compared to the FDMA scheme. That is because the NOMA scheme is known to have a higher spectrum efficiency compared to the FDMA scheme.

    Fig.3 Optimal deployment location for FDMA scheme versus r*

    Fig.4 compares the sum rate of the 3 different schemes versus differentr*. It can be noted that the sum rate of the proposed DP scheme decreases asr*increases. This phenomenon is consistent with Remark 2. Also, it can be observed that the proposed DP scheme outperforms the FDMA scheme and the POWD scheme from the perspective of sum rate. The proposed DP scheme can achieve a higher sum rate compared to the FDMA scheme, because of the employed NOMA manner. The proposed DP scheme can obtain a higher sum rate compared to the POWD scheme, because of the optimal UAV location deployment. Moreover, it should be pointed out that whenr*=1 bps/Hz, the POWD scheme cannot satisfy the QoS constraint, and therefore the sum rate drops to zero. Therefore, the conclusion can be drawn that by designing the optimal UAV’s deployment location, not only the sum rate can be enhanced, the QoS of each user can also be assured.

    Fig.4 Sum rate versus r*

    4 Conclusion

    In this paper, the optimal UAV’s deployment problem is studied in a two-user case. In order to maximize users’ sum rate, an optimization problem is first constructed, considering the QoS and power constraints. Then, a feasible solution region of the problem is reduced to a line segment between the two users. This conclusion can help us further reduce the original optimization problem to a simplified one. Next, by giving a UAV’s location and utilizing the optimal power allocation strategy which is relevant to the UAV’s location, the optimization problem is reduced to a univariate problem. The analytical solution to the simplified problem under a certain situation is provided, and moreover, a generalized algorithm is proposed to further determine the optimal UAV’s location. Simulation results are presented to demonstrate effectiveness of the proposed DP scheme in maximizing the sum rate and its advantages over the FDMA and POWD schemes.

    猜你喜歡
    控制率進(jìn)展例數(shù)
    Micro-SPECT/CT應(yīng)用進(jìn)展
    無(wú)錫茶園不同修剪模式對(duì)茶小綠葉蟬發(fā)生量的影響
    茶葉(2021年1期)2021-04-13 06:21:34
    人工膝關(guān)節(jié)翻修例數(shù)太少的醫(yī)院會(huì)增加再翻修率:一項(xiàng)基于23 644例的研究
    更正
    家庭醫(yī)生式服務(wù)對(duì)社區(qū)原發(fā)性高血壓患者治療依從性及控制率的影響
    患者術(shù)后躁動(dòng)危險(xiǎn)因素的Logistic回歸分析
    拉薩市城關(guān)區(qū)2014 年社區(qū)人群高血壓的患病率、知曉率、治療率和控制率調(diào)查分析
    西藏科技(2015年6期)2015-09-26 12:12:09
    鄭州市某三甲醫(yī)院職工高血壓知曉率、治療率、控制率及急性并發(fā)癥調(diào)查
    眼外傷遲發(fā)性繼發(fā)青光眼的臨床分析
    寄生胎的診治進(jìn)展
    美女福利国产在线| 久久人妻熟女aⅴ| 狠狠婷婷综合久久久久久88av| 性高湖久久久久久久久免费观看| 亚洲九九香蕉| 这个男人来自地球电影免费观看| 国产成人精品无人区| cao死你这个sao货| 一区二区三区精品91| 女警被强在线播放| 成人国产av品久久久| 免费高清在线观看日韩| 亚洲一码二码三码区别大吗| 成人手机av| 热99re8久久精品国产| 在线av久久热| 免费av中文字幕在线| 久久99热这里只频精品6学生| 精品高清国产在线一区| 男人爽女人下面视频在线观看| 一边摸一边抽搐一进一出视频| 久久热在线av| 亚洲精品粉嫩美女一区| 黄色视频不卡| 黄频高清免费视频| 日本a在线网址| 极品少妇高潮喷水抽搐| 丰满饥渴人妻一区二区三| 在线观看www视频免费| 超碰97精品在线观看| 黄色视频在线播放观看不卡| 男人爽女人下面视频在线观看| 啦啦啦啦在线视频资源| 国产深夜福利视频在线观看| 国产真人三级小视频在线观看| 91麻豆精品激情在线观看国产 | 日韩视频一区二区在线观看| 最近最新免费中文字幕在线| 中文字幕人妻熟女乱码| 777米奇影视久久| 久久热在线av| 老司机亚洲免费影院| 亚洲中文字幕日韩| 啦啦啦 在线观看视频| 一区在线观看完整版| 欧美久久黑人一区二区| 中文字幕制服av| 亚洲精品美女久久久久99蜜臀| 香蕉国产在线看| 9色porny在线观看| 国产无遮挡羞羞视频在线观看| 亚洲av美国av| 久久国产精品人妻蜜桃| 老汉色∧v一级毛片| www.999成人在线观看| 久久九九热精品免费| 成年女人毛片免费观看观看9 | 每晚都被弄得嗷嗷叫到高潮| 新久久久久国产一级毛片| 国产又色又爽无遮挡免| 日韩,欧美,国产一区二区三区| 欧美xxⅹ黑人| 国产色视频综合| 日韩大片免费观看网站| 久久国产精品人妻蜜桃| 欧美人与性动交α欧美软件| 动漫黄色视频在线观看| 天天躁狠狠躁夜夜躁狠狠躁| 国产一区二区激情短视频 | 日韩中文字幕欧美一区二区| 桃花免费在线播放| 老司机影院毛片| 中亚洲国语对白在线视频| 久久香蕉激情| 久久99热这里只频精品6学生| av不卡在线播放| 麻豆乱淫一区二区| 亚洲国产看品久久| 久久99一区二区三区| 一区在线观看完整版| 亚洲欧洲精品一区二区精品久久久| 欧美激情久久久久久爽电影 | 岛国毛片在线播放| av片东京热男人的天堂| 精品久久久精品久久久| 精品视频人人做人人爽| 一级片免费观看大全| 久久久国产一区二区| 99久久综合免费| 成人av一区二区三区在线看 | 国产亚洲精品一区二区www | 少妇精品久久久久久久| 亚洲黑人精品在线| 高清在线国产一区| 999久久久精品免费观看国产| 国产精品久久久人人做人人爽| 久久人妻福利社区极品人妻图片| av网站在线播放免费| www日本在线高清视频| 日本欧美视频一区| 中亚洲国语对白在线视频| 久久影院123| 激情视频va一区二区三区| 亚洲国产精品999| 久久九九热精品免费| 人人妻人人添人人爽欧美一区卜| 18禁观看日本| 精品免费久久久久久久清纯 | 人人妻人人澡人人看| 啦啦啦视频在线资源免费观看| 美女视频免费永久观看网站| 日韩视频一区二区在线观看| 熟女少妇亚洲综合色aaa.| 老司机在亚洲福利影院| 99re6热这里在线精品视频| 亚洲天堂av无毛| 久久 成人 亚洲| 777久久人妻少妇嫩草av网站| 丝袜在线中文字幕| 欧美另类一区| 国产一卡二卡三卡精品| 精品亚洲乱码少妇综合久久| 黄色视频在线播放观看不卡| 久久人妻熟女aⅴ| 免费看十八禁软件| 黄色片一级片一级黄色片| 亚洲国产中文字幕在线视频| av在线播放精品| 国产精品久久久久久精品电影小说| 老熟妇仑乱视频hdxx| 国产又爽黄色视频| 欧美黄色片欧美黄色片| 亚洲九九香蕉| 又大又爽又粗| 在线观看免费高清a一片| 91字幕亚洲| 亚洲av日韩精品久久久久久密| 国产精品久久久av美女十八| 成人国语在线视频| 老司机影院成人| 一级毛片女人18水好多| 精品高清国产在线一区| 亚洲色图综合在线观看| 久久精品亚洲熟妇少妇任你| 午夜两性在线视频| 十八禁高潮呻吟视频| 亚洲国产精品999| 国产精品久久久久久人妻精品电影 | 又紧又爽又黄一区二区| videos熟女内射| 国产精品二区激情视频| 国产成人精品久久二区二区91| 色婷婷av一区二区三区视频| 国产日韩一区二区三区精品不卡| www.自偷自拍.com| 亚洲精华国产精华精| 亚洲情色 制服丝袜| 999久久久国产精品视频| 黄频高清免费视频| 日本av手机在线免费观看| 国产在线一区二区三区精| 51午夜福利影视在线观看| 国产高清videossex| 美女视频免费永久观看网站| 性色av乱码一区二区三区2| 法律面前人人平等表现在哪些方面 | 国产免费现黄频在线看| 夫妻午夜视频| 亚洲精品一区蜜桃| 免费看十八禁软件| 亚洲精品国产av成人精品| h视频一区二区三区| 亚洲熟女精品中文字幕| 美女国产高潮福利片在线看| 日本精品一区二区三区蜜桃| 日韩中文字幕视频在线看片| 中文字幕制服av| 亚洲七黄色美女视频| 久久影院123| 久久精品国产a三级三级三级| 久久99一区二区三区| 黄片播放在线免费| 国产又爽黄色视频| 国产成人av教育| 欧美精品啪啪一区二区三区 | 国产精品免费大片| av线在线观看网站| 国产黄频视频在线观看| 老司机亚洲免费影院| 亚洲精品一二三| 视频区图区小说| 欧美国产精品va在线观看不卡| av视频免费观看在线观看| 欧美人与性动交α欧美精品济南到| 精品国产国语对白av| 另类亚洲欧美激情| 日韩大片免费观看网站| 国产高清视频在线播放一区 | 一区二区三区激情视频| 国产亚洲精品久久久久5区| 国产高清国产精品国产三级| 无遮挡黄片免费观看| 国产黄色免费在线视频| 两性午夜刺激爽爽歪歪视频在线观看 | 国产精品亚洲av一区麻豆| 国产日韩欧美视频二区| 性色av乱码一区二区三区2| 黄片播放在线免费| 国产淫语在线视频| 免费不卡黄色视频| 国产一级毛片在线| 又大又爽又粗| 五月天丁香电影| 亚洲久久久国产精品| 两人在一起打扑克的视频| 久久久久国产精品人妻一区二区| 精品国产乱码久久久久久男人| 国产精品一区二区在线不卡| 亚洲伊人色综图| 一个人免费在线观看的高清视频 | 国产男人的电影天堂91| 国产免费视频播放在线视频| 欧美日韩精品网址| 国产成人系列免费观看| 成人免费观看视频高清| 国产欧美日韩一区二区精品| 久久久久久久精品精品| 国产精品香港三级国产av潘金莲| 日本wwww免费看| 亚洲精品一卡2卡三卡4卡5卡 | 国产高清videossex| 精品亚洲乱码少妇综合久久| 国产成人影院久久av| 一本久久精品| 99精品欧美一区二区三区四区| 人人妻人人添人人爽欧美一区卜| h视频一区二区三区| 亚洲欧美成人综合另类久久久| 欧美日韩av久久| 美女高潮到喷水免费观看| 午夜激情久久久久久久| 丁香六月天网| 久久久精品国产亚洲av高清涩受| 黄色 视频免费看| 精品福利永久在线观看| 一区二区三区乱码不卡18| a级片在线免费高清观看视频| 国产成人免费观看mmmm| 欧美日韩亚洲高清精品| 亚洲精品久久久久久婷婷小说| 天天躁日日躁夜夜躁夜夜| 欧美激情 高清一区二区三区| 日韩中文字幕视频在线看片| 日本五十路高清| 嫁个100分男人电影在线观看| 人妻人人澡人人爽人人| 色94色欧美一区二区| 久久久久精品国产欧美久久久 | 久9热在线精品视频| 欧美激情久久久久久爽电影 | 免费不卡黄色视频| 久久久久久久国产电影| 成人手机av| 色婷婷久久久亚洲欧美| 亚洲性夜色夜夜综合| 国产日韩一区二区三区精品不卡| 久久精品国产亚洲av香蕉五月 | 成人黄色视频免费在线看| 欧美在线一区亚洲| 夜夜骑夜夜射夜夜干| 精品少妇黑人巨大在线播放| 久久久久精品国产欧美久久久 | 久久久精品国产亚洲av高清涩受| 悠悠久久av| 电影成人av| 亚洲精品国产av成人精品| www.av在线官网国产| 中国国产av一级| 国产精品久久久av美女十八| 欧美日韩一级在线毛片| 国产一级毛片在线| 亚洲美女黄色视频免费看| 水蜜桃什么品种好| 纵有疾风起免费观看全集完整版| netflix在线观看网站| 亚洲,欧美精品.| 亚洲精品国产一区二区精华液| 丝瓜视频免费看黄片| 国产黄频视频在线观看| 97精品久久久久久久久久精品| 国产有黄有色有爽视频| 国产免费一区二区三区四区乱码| 亚洲精品国产精品久久久不卡| av天堂久久9| 国产精品香港三级国产av潘金莲| 国产男人的电影天堂91| 亚洲欧美色中文字幕在线| 亚洲国产av影院在线观看| 国产视频一区二区在线看| 成年美女黄网站色视频大全免费| 午夜91福利影院| 十八禁网站免费在线| 多毛熟女@视频| 无遮挡黄片免费观看| 国产成人一区二区三区免费视频网站| 悠悠久久av| 亚洲五月婷婷丁香| 亚洲中文字幕日韩| 久久精品成人免费网站| 国产精品熟女久久久久浪| videosex国产| 国产1区2区3区精品| 亚洲国产精品999| 黑人猛操日本美女一级片| tube8黄色片| 视频区图区小说| 丝袜在线中文字幕| 69精品国产乱码久久久| 12—13女人毛片做爰片一| 亚洲五月婷婷丁香| 热re99久久精品国产66热6| 国产黄色免费在线视频| 麻豆乱淫一区二区| 一区二区三区精品91| 欧美日韩精品网址| 久久免费观看电影| 国产精品99久久99久久久不卡| 免费观看人在逋| 亚洲中文日韩欧美视频| 亚洲中文av在线| 黄片播放在线免费| 午夜免费观看性视频| 久久性视频一级片| 9191精品国产免费久久| 精品人妻一区二区三区麻豆| 国产成人精品无人区| 久久热在线av| 精品国产超薄肉色丝袜足j| 天天添夜夜摸| 国产成人精品久久二区二区免费| 国产精品九九99| 亚洲 欧美一区二区三区| 人妻一区二区av| 久久久久精品国产欧美久久久 | 亚洲av男天堂| 国产亚洲av片在线观看秒播厂| 99久久精品国产亚洲精品| 乱人伦中国视频| 热99re8久久精品国产| 狠狠精品人妻久久久久久综合| 久久精品亚洲av国产电影网| 国产视频一区二区在线看| 视频在线观看一区二区三区| 一级黄色大片毛片| 大香蕉久久成人网| 在线观看www视频免费| 最新的欧美精品一区二区| 亚洲欧美日韩另类电影网站| 国产精品偷伦视频观看了| 亚洲欧美清纯卡通| 1024香蕉在线观看| 精品久久久久久电影网| a级毛片在线看网站| 亚洲欧美日韩高清在线视频 | 婷婷成人精品国产| cao死你这个sao货| 一级a爱视频在线免费观看| 纵有疾风起免费观看全集完整版| 国产精品1区2区在线观看. | 亚洲精品一二三| 伦理电影免费视频| 一本一本久久a久久精品综合妖精| 国产高清videossex| 欧美午夜高清在线| 亚洲国产精品一区三区| 十八禁网站网址无遮挡| 少妇猛男粗大的猛烈进出视频| 欧美日本中文国产一区发布| 国产成人免费无遮挡视频| 啦啦啦 在线观看视频| 一区二区三区四区激情视频| 国产一区二区激情短视频 | 纵有疾风起免费观看全集完整版| 一级a爱视频在线免费观看| 久久99一区二区三区| 亚洲国产欧美网| 亚洲国产欧美网| 999精品在线视频| 亚洲欧美精品自产自拍| 欧美日韩国产mv在线观看视频| 亚洲成av片中文字幕在线观看| 日本撒尿小便嘘嘘汇集6| 国产日韩欧美视频二区| 男女免费视频国产| 中文字幕av电影在线播放| 国产主播在线观看一区二区| 两人在一起打扑克的视频| 另类精品久久| 性色av乱码一区二区三区2| 国产免费视频播放在线视频| 欧美午夜高清在线| 精品久久久久久电影网| 欧美精品亚洲一区二区| 成年美女黄网站色视频大全免费| 欧美日韩精品网址| 91国产中文字幕| 精品国产超薄肉色丝袜足j| 波多野结衣一区麻豆| 成人av一区二区三区在线看 | 日韩中文字幕欧美一区二区| 亚洲人成电影免费在线| 亚洲成人免费av在线播放| 首页视频小说图片口味搜索| 国产xxxxx性猛交| 大片电影免费在线观看免费| 亚洲成人国产一区在线观看| xxxhd国产人妻xxx| 国产免费现黄频在线看| 两性午夜刺激爽爽歪歪视频在线观看 | 精品国内亚洲2022精品成人 | 成人国产一区最新在线观看| 桃花免费在线播放| 久久亚洲精品不卡| 91老司机精品| 女人久久www免费人成看片| 丝袜美足系列| 性色av乱码一区二区三区2| 丝袜脚勾引网站| 交换朋友夫妻互换小说| 麻豆乱淫一区二区| 在线观看免费午夜福利视频| 新久久久久国产一级毛片| av又黄又爽大尺度在线免费看| 久热这里只有精品99| 欧美久久黑人一区二区| 国产一区二区三区综合在线观看| 国产1区2区3区精品| 丝袜美腿诱惑在线| 五月天丁香电影| 亚洲一区二区三区欧美精品| 成人手机av| 国产一级毛片在线| 日本vs欧美在线观看视频| tube8黄色片| 国产精品欧美亚洲77777| 午夜福利,免费看| 少妇猛男粗大的猛烈进出视频| 日韩欧美免费精品| 亚洲午夜精品一区,二区,三区| 18在线观看网站| 12—13女人毛片做爰片一| 性少妇av在线| 欧美在线黄色| www.熟女人妻精品国产| 亚洲男人天堂网一区| 在线观看免费高清a一片| 成人亚洲精品一区在线观看| 一区二区三区四区激情视频| 日韩,欧美,国产一区二区三区| 美女福利国产在线| videosex国产| 精品高清国产在线一区| 性高湖久久久久久久久免费观看| 欧美另类一区| 深夜精品福利| 91精品国产国语对白视频| 俄罗斯特黄特色一大片| 亚洲精品一卡2卡三卡4卡5卡 | 淫妇啪啪啪对白视频 | 超色免费av| 亚洲一区中文字幕在线| 91成年电影在线观看| 国产av国产精品国产| 国产伦理片在线播放av一区| 大片电影免费在线观看免费| 久久久国产欧美日韩av| 久久香蕉激情| 老汉色∧v一级毛片| 欧美日韩成人在线一区二区| 五月天丁香电影| 久久人妻福利社区极品人妻图片| 丝袜美足系列| 久久久国产精品麻豆| 日本av手机在线免费观看| 人人妻人人爽人人添夜夜欢视频| av天堂久久9| 另类亚洲欧美激情| 国产成人啪精品午夜网站| 男人添女人高潮全过程视频| 亚洲av男天堂| videos熟女内射| 免费不卡黄色视频| 97在线人人人人妻| 日韩制服骚丝袜av| 女人被躁到高潮嗷嗷叫费观| 国产色视频综合| 一边摸一边做爽爽视频免费| 伊人亚洲综合成人网| 老熟妇乱子伦视频在线观看 | 亚洲国产中文字幕在线视频| 日韩视频在线欧美| 高潮久久久久久久久久久不卡| 叶爱在线成人免费视频播放| 国产日韩欧美视频二区| 菩萨蛮人人尽说江南好唐韦庄| 欧美97在线视频| 91大片在线观看| 女人久久www免费人成看片| 岛国在线观看网站| 久久久国产成人免费| 精品亚洲成国产av| 自拍欧美九色日韩亚洲蝌蚪91| 亚洲成av片中文字幕在线观看| 国产在视频线精品| 久久精品亚洲av国产电影网| 精品亚洲成国产av| 国产精品一区二区免费欧美 | 亚洲一区中文字幕在线| 久久香蕉激情| 美女中出高潮动态图| 精品国内亚洲2022精品成人 | 欧美激情极品国产一区二区三区| 夫妻午夜视频| 国产一区二区激情短视频 | 成年人黄色毛片网站| 精品亚洲成a人片在线观看| 一级毛片电影观看| 国产精品.久久久| 久久久久网色| 波多野结衣一区麻豆| 亚洲第一av免费看| 精品一区二区三区av网在线观看 | 日韩人妻精品一区2区三区| 18禁观看日本| 一级毛片电影观看| 午夜福利在线免费观看网站| 99热全是精品| 久久久久久亚洲精品国产蜜桃av| 午夜福利,免费看| 亚洲欧美清纯卡通| 日本av免费视频播放| 亚洲成人免费av在线播放| 国产一区二区 视频在线| 黑丝袜美女国产一区| 亚洲欧美激情在线| 黄色片一级片一级黄色片| 国产av一区二区精品久久| 亚洲av片天天在线观看| a在线观看视频网站| 亚洲精品一区蜜桃| 丰满迷人的少妇在线观看| 大陆偷拍与自拍| 少妇 在线观看| 一区二区av电影网| 国产av一区二区精品久久| 王馨瑶露胸无遮挡在线观看| 中国美女看黄片| 好男人电影高清在线观看| 久久久精品94久久精品| 大陆偷拍与自拍| 动漫黄色视频在线观看| 亚洲国产欧美在线一区| 十八禁网站免费在线| a级毛片黄视频| 三级毛片av免费| 国产一卡二卡三卡精品| 中文字幕精品免费在线观看视频| 成人黄色视频免费在线看| 男女无遮挡免费网站观看| 91精品伊人久久大香线蕉| 中国美女看黄片| 日本91视频免费播放| 一级毛片女人18水好多| 久久久久久久久久久久大奶| 伊人久久大香线蕉亚洲五| 成年女人毛片免费观看观看9 | 99久久人妻综合| 国产一区二区 视频在线| 亚洲精品中文字幕一二三四区 | 国产免费现黄频在线看| 亚洲欧美激情在线| av又黄又爽大尺度在线免费看| 黄色视频不卡| 一级黄色大片毛片| 国产精品亚洲av一区麻豆| 在线天堂中文资源库| 国产精品免费视频内射| 欧美黄色淫秽网站| 精品少妇黑人巨大在线播放| 午夜激情av网站| 两人在一起打扑克的视频| 精品少妇黑人巨大在线播放| 黄色视频在线播放观看不卡| 操美女的视频在线观看| 国产欧美日韩精品亚洲av| 亚洲国产精品成人久久小说| 大型av网站在线播放| 好男人电影高清在线观看| 国产日韩一区二区三区精品不卡| 亚洲av日韩在线播放| 国产深夜福利视频在线观看| 日韩欧美一区二区三区在线观看 | 十分钟在线观看高清视频www| 亚洲精品美女久久久久99蜜臀| a级毛片黄视频| 日本vs欧美在线观看视频| 99国产精品免费福利视频| 午夜激情av网站| 夜夜夜夜夜久久久久| 在线精品无人区一区二区三| 国产精品99久久99久久久不卡| 欧美黄色淫秽网站| 国产三级黄色录像| 久热爱精品视频在线9| 在线av久久热|