IEEE C802.16m-07/060. IEEE Broadband Wireless Access Working Group <

Transcription

1 IEEE C80.6m-07/060 Poject Title Date Submitted IEEE 80.6 Boadband Wiele Acce Woking Goup < Coelation Model fo Shadow Fading Simulation Souce() I-Kang Fu, Chi-Fang Li, Ting-Chen Song, Wen-Ho Sheen NCTU/ITRI 00 Ta Hueh Road, Hinchu, Taiwan 300, ROC. Re: Abtact IEEE 80.6m-07/005, Call fo Contibution on Evaluation Methodology and Key Citeia fo P80.6m Advanced Ai Inteface Thi contibution intoduce the hadow fading coelation model and thei imulation methodologie fo ytem level imulation. Pupoe Popoe the coelation model fo hadow fading imulation into the IEEE 80.6m evaluation methodology Notice Releae Patent Policy and Pocedue Thi document ha been pepaed to ait IEEE It i offeed a a bai fo dicuion and i not binding on the contibuting individual() o oganization(). The mateial in thi document i ubject to change in fom and content afte futhe tudy. The contibuto() eeve() the ight to add, amend o withdaw mateial contained heein. The contibuto gant a fee, ievocable licene to the IEEE to incopoate mateial contained in thi contibution, and any modification theeof, in the ceation of an IEEE Standad publication; to copyight in the IEEE name any IEEE Standad publication even though it may include potion of thi contibution; and at the IEEE ole dicetion to pemit othe to epoduce in whole o in pat the eulting IEEE Standad publication. The contibuto alo acknowledge and accept that thi contibution may be made public by IEEE The contibuto i familia with the IEEE 80.6 Patent Policy and Pocedue < including the tatement IEEE tandad may include the known ue of patent(), including patent application, povided the IEEE eceive auance fom the patent holde o applicant with epect to patent eential fo compliance with both mandatoy and optional potion of the tandad. Ealy dicloue to the Woking Goup of patent infomation that might be elevant to the tandad i eential to educe the poibility fo delay in the development poce and inceae the likelihood that the daft publication will be appoved fo publication. Pleae notify the Chai <mailto:chai@wieleman.og> a ealy a poible, in witten o electonic fom, if patented technology (o technology unde patent application) might be incopoated into a daft tandad being developed within the IEEE 80.6 Woking Goup. The Chai will dicloe thi notification via the IEEE 80.6 web ite < Page of 5

2 IEEE C80.6m-07/060 Coelation Model fo Shadow Fading Simulation I-Kang Fu, Chi-Fang Li, Ting-Chen Song, Wen-Ho Sheen NCTU/ITRI Intoduction In ytem level imulation, the hadow fading i uually modeled by the log-nomal andom vaiable. When dynamic imulation i conideed fo imulating the channel vaiation due to ue mobility, the hadow fading effect hall be updated fom time to time. Due to the natue of the popagation envionment, the hadow fading fo the ame adio link at the neaby location will not change vey much. Theefoe, cetain coelation hall be applied when imulating the hadow fading effect, and thi kind of coelation i called auto-coelation fo hadow fading. In addition, multiple adio link may be imulated fo the ame ue in multi-cell envionment. Fo the adio link which ha imila popagation path, the hadow fading expeienced by each of them will not diffe too much. In ode to pope model thi effect, the co-coelation model hall be conideed when imulating the hadow fading effect fo multiple adio link. In the following text popoal, both the auto-coelation and co-coelation model fo hadow fading will be intoduced. Moeove, the coeponding imulation methodology will alo be pefomed. Text Popoal Stat of the Text Add the following text to the evaluation methodology document Coelation Model fo Shadow Fading By given mean (uually equal to 0dB) and tandad deviation, the level of hadow fading (in db) i uually imulated by dopping a Nomal ditibuted andom vaiable. Thi efe to typical log-nomal hadow fading model. Howeve, the coelation model hall be conideed to captue the chaacteitic of the popagation envionment when pefoming the ytem level imulation. Two type of coelation model fo hadow fading ae intoduced a following. Auto-coelation Model fo Shadow Fading The auto-coelation of hadow fading indicate the coelation among the hadowing effect among the ame adio link in diffeent location, which i illutated in Figue. Page of 5

3 IEEE C80.6m-07/060 Fig. Auto-coelation of hadow fading A popula model popoed by Gudmundon [] i well undetood in following fom []: Vx - ln d co ( Vx) e (3) whee ρ i the coelation coefficient and Δx i the ditance between adjacent obevation location. d co i the de-coelation ditance, which wa uggeted a 0m in vehicula tet envionment in []. The way to apply thi model in ytem level imulation i biefly ummaized a follow: Conide the log-nomal hadow fading model with zeo mean and vaiance σ in db. If L i the log-nomal component at poition P and L i the one fo P, which i Δx away fom P. Then L will be nomally ditibuted in db with mean ρ(δx) L and vaiance ( -[ρ(δx)] ) σ. Thi eult can be deived though the analyi in Appendix A. Co-coelation Model fo Shadow Fading Intead of the afoementioned auto-coelation model, the co-coelation of hadow fading indicate the coelation among the hadow effect of diffeent adio link at the ame time. In geneal, longe common popagation path will induce highe coelation. Fo example, the co-coelation among the hadow fading of the adio link in Figue (a) hould be lowe than the one in Figue (b). Page 3 of 5

4 IEEE C80.6m-07/060 Fig. Co-coelation of hadow fading A imple co-coelation model popoed in [3] can be conideed fo thi: q if q 60 ( q) if q > 60 o o (4) whee i the coelation coefficient and q i the angle of aival diffeence. In ode to apply thi effect in ytem level imulation, following pocedue can be conideed:. Conide the hadow fading effect of the adio link of one mobile tation and N bae tation at pecific time intance, dop N independent Nomal ditibuted andom vaiable C [ X, X, X 3,, X N ].. Obtain the matix G, which i N N G N N whee i the coelation coefficient of the hadow fading component among the adio link to bae tation # and #. Since G i a ymmetic and poitive definite matix, it can be decompoed into a lowe and uppe T tiangula matix by Choleky decompoition technique. Theefoe, G C C, whee C i an uppe tiangula matix. 3. Y XC [ Y Y Y Y ],, 3,, N will be the co-coelated log-nomal hadow fading component fo each adio link. (5) End of the Text Page 4 of 5

5 IEEE C80.6m-07/060 Refeence [] Gudmundon, M., Coelation Model fo Shadow Fading in Mobile Radio Sytem, Electonic Lette, pp.45-46, vol. 7, No 3, Nov. 99. [] ETSI TR 0. v3..0, Selection pocedue fo the choice of adio tanmiion technologie of the UMTS, Ap [3] T. Klingenbunn and P. Mogenen, Modeling Co-Coelated Shadowing in Netwok Simulation, IEEE Vehicula Technology Confeence, pp.407-4, Vol.3, Sep Appendix A Conide X and Y ae both Nomal ditibuted andom vaiable. Given Y y and the coelation coefficient a ρ, the pobability ditibution function f X ( x y ) can be deived a: Conide m, m and, ae the mean and vaiance of X and Y f f ( x y) X Y ( x, y) f ( y) - - x - m x - m y - m y - m ( y - m ) ( ) p - p exp ( ) ( )( ) ( ) exp - x - m y - m - - x - m x - m y - m y - m y - m exp ( ) - ( )( ) + ( ) -( - )( ) p ( - ) ( - ) exp - p ( - ) ( ) x - m - ( y - m ) exp - p ( - ) ( - ) \ the mean of f ( x y) i m + y - m and vaiance i ( - ) ( ) X If X and Y ae both with zeo mean and vaiance σ, and the coelation coefficient between X and Y ae equal to ρ. Then, the mean of f X ( x y ) will beρy and it vaiance will beσ (-ρ ). Page 5 of 5