(Special Paper) 2, 25 (JBE Vol. 2, No., January 25) http://dx.doi.org/.599/jbe.25.2..3 ISSN 2287-937 (Online) ISSN 226-7953 (Print) DVB-NGH 2x2 MIMO SM a), a), b) Study on Improved Polarized 2x2 MIMO Spatial Multiplexing Method for DVB-NGH System Jae Hyun Seo a), Heung Mook Kim a), and Dong Seog Han b). MIMO. DVB-NGH 2x2 MIMO SM.,, 2.. SM. Abstract Recently terrestrial digital broadcasting systems have experienced a growth with the demand of high data rate. In order to meet such demand, the MIMO technology has received a wide attention. This paper proposes a pre-coding method, which provides high space channel correlation for the improved performance over terrestrial broadcasting channels when the polarized 2x2 MIMO SM is adopted for DVB-NGH systems. When signals with two different modulation orders are transmitted through two antennas, a method that is based on non-uniform power is also proposed for improved reception performance. To optimize the proposed method, phase shifting values for the pre-coding method and appropriate unequal power ratio are obtained. These obtained parameters are applied to a terrestrial broadcasting system, and then the performance improvement over the conventional SM is shown through computer simulations. Keyword : DVB-NGH, OFDM, MIMO, terrestrial, spatial multiplexing a) (Broadcasting Systems Research Department, Elecktronics and Telecommunications Research Institute) b) (School of Electronics Engineering, Kyungpook National University) Corresponding Author : (Dong Seog Han) E-mail: dshan@knu.ac.kr Tel: +82-53-95-669 ORCID: http://orcid.org/-2-7769-236. [4--2-2, ] Manuscript received November 3, 24 Revised January 9, 25 Accepted January 9, 25
(JBE Vol. 2, No., January 25). SDTV, HDTV 3DTV., UHDTV.,, MIMO(multiple input multiple output) [][2]., LTE, WiMAX [3]., LOS(line of sight). DTV DVB-T(digital video broadcasting-terrestrial) 2 DTV DVB-T2. OFDM(orthogonal frequency division multiplexing)., (GI, guard interval) FFT, (pilot) [4]. DVB-T2 256QAM, FFT 32K, %., (convolutional code) (Reed Solomon) LDPC(low density parity check) BCH(Bose Chaudhri Hocquenghem) [5]. ATSC(advanced television systems committee) ADT(augmented data transmission). ADT, DTV, Mbps., RF [6]., ATSC-ADT [7]. MIMO, (SM, spatial multiplexing). DVB-T2 DVB-T2 MIMO., 2x2 MIMO LOS, [8]., DVB-T2 MIMO SM SISO(single input single output) [9]. DVB-T2 MIMO DVB-NGH(digital video broadcasting-next generation handheld) 2x2 MIMO SM [].., MIMO DVB-NGH SM. MIMO SM LOS., 2x2 MIMO SM 2. 2 MIMO SM DVB-NGH MIMO, MIMO SM. 3 4.
. MIMO SM. MIMO SM DVB-NGH MIMO SM. OFDM 2x2 MIMO SM. 2x2 MIMO SM 2., QPSK 2 2 4 2., 6 bpc(bits per cell), 8 bpc, bpc. 6 bpc QPSK 6QAM, 8 bpc 6QAM 6QAM, bpc 6QAM 64QAM 2. DVB-NGH 2 DVB-T2 6/64k LDPC, DVB-T2, MIMO,.,. DVB-NGH, MIMO,, MIMO 4., DVB-NGH 2x2 MIMO []., DVB-NGH (TI, time interleaver), (TFS, time frequency slicing), 2x2 MIMO, Input stream FEC Enc. Interleaver MIMO Enc. OFDM Mod. 2x2 MIMO Channel Output stream FEC Dec. Deinterleaver MIMO Dec. OFDM Dem.. OFDM 2x2 MIMO SM Fig.. Block diagram of conventional 2x2 MIMO SM for OFDM system 2. DVB-NGH 2x2 MIMO SM Fig. 2. 2x2 MIMO SM method for DVB-NGH system
(JBE Vol. 2, No., January 25) [2][3]., (VHF, very high frequency) (UHF, ultra high frequency)., MIMO 2 ( ). DVB-NGH Alamouti DVB-T2 MIMO. MIMO DVB-NGH 2 2x2 MIMO SM. LOS, (Ricean),. DVB-NGH SM esm(enhanced SM). 3 DVB-NGH 2x2 MIMO esm 2 2x2 MIMO SM 3. DVB-NGH 2x2 MIMO esm Fig. 3. 2x2 MIMO esm method for DVB-NGH system 4. DVB-NGH 2x2 MIMO esm-ph Fig. 4. 2x2 MIMO esm-ph method for DVB-NGH system
(precoding). DVB- NGH 3 esm PH (Phase-Hopping). 4 DVB-NGH 2x2 MIMO esm-ph 3 2x2 MIMO esm 2 OFDM. PH LOS burst [3]. MIMO SM 2 QPSK, 6QAM 2x2 MIMO 5. QPSK, 6QAM QPSK 6QAM 64. 2 Golden code [4]. 2. MIMO SM MIMO SM 2.., 2.., 2.8 2 Rx Ant..6.5.4.2 -.2 -.4 -.6 h, h,2.5 -.5 - -.5 -.8 -.8 -.6 -.4 -.2.2.4.6.8.8.6.4.2 Tx Ant. 2 h 2, -2-2 -.5 - -.5.5.5 2 2.5.5 Rx Ant. 2 -.2 -.4 -.6 h 2,2 -.5 - -.8 -.5 - - -.8 -.6 -.4 -.2.2.4.6.8-2 -2 -.5 - -.5.5.5 2 5. MIMO SM QPSK/6QAM Fig. 5. QPSK/6QAM signal constellations of transmitted and received antennas when channel correlation
(JBE Vol. 2, No., January 25) h, x Unequal Power [ y ] y, = Dx T y 2 y y 2 Precoder r = [ r ] T r, 2 = Qy r r 2 h2, h, 2 h 2,2 ML Decoder xˆ 6. 2x2 MIMO SM Fig. 6. Block diagram of unequal power-precoded 2x2 MIMO SM system. 6 2x2 MIMO SM., x ()~(5) (6). cos sin sin cos x., y y x., T transpose., (3) 2., 2.,. LOS K (Ricean), XPD(cross-polar discrimination) = db 9, (uncoded) BER., XPD (7). log log, r (4). r y, (8),., (5) 2. cos sin sin cos
-.2 -.3 a=3/4 a=2/3 a=/2 a=/3 a=/4 Average Uncoded BER -.4 -.5 -.6 -.7 2 3 4 5 6 7 8 9 Rotation Angle of Precoder [degree] 7. (SNR = 7 db) Fig. 7. Performances of average uncoded BER according to rotation angles of precoder and power ratio when SNR = 7 db, 4. /4, /3, /2, 2/3, 3/4., /3 QPSK 6QAM 2. 7 SNR = 7 db (uncoded) BER. /3, 2~3 6~7 (uncoded) BER., 8 SNR db (uncoded) BER. /3, 3~6 (uncoded) BER., SNR /3. 2x2 MIMO SM., SM (precoded) SM (unequal power, UP)- SM. ( ) (9). or 9. 9 64 - SM.. SM SM 44%, - SM 58%., - SM.
(JBE Vol. 2, No., January 25) -.8 a=3/4 a=2/3 a=/2 a=/3 a=/4 Average Uncoded BER -.9 2 3 4 5 6 7 8 9 Rotation Angle of Precoder [degree] 8. (SNR db) Fig. 8. Performances of average uncoded BER according to rotation angles of precoder and power ratio when SNR db.3 Conventional SM Precoded SM UP-Precoded SM.25 Minimum Distance.2.5..5 2 3 4 5 6 7 8 9 Channel Phase Difference [degree] 9. Fig. 9. Minimum distances according to channel phase differences
. SM Table. Comparison between average minimum distance of constellation for each SM methods SM method Average minimum distance Conventional SM Precoded SM UP-Precoded SM.226.747.96 2x2 MIMO SM 2 QPSK, 6QAM 2x2 MIMO. (6) 64, 64. 64, 64. 2x2 MIMO SM. 2. DVB-T2 FFT 4K, /4, FEC LDPC (frame size 62 bits, code rate = 4/9, 2/3). 2 QPSK 6QAM. MIMO Helsinki2, (Ricean factor) K, XPD = 6 db, = 33.3 Hz [9]. 2. Table 2. Simulation parameters Term FFT size Parameters 4K Guard Interval /4 FEC LDPC (frame size 62 bits) Code Rate 4/9, 2/3 Modulation Channel Model Doppler Frequency QPSK, 6QAM Helsinki2 outdoor channel (Rice K, XPD = 6 db) 33.3 Hz.5 Tx Ant. 2 Rx Ant..5.5 -.5 - h, h,2.5 -.5 - -.5 -.5 -.5 - -.5.5.5.5 Tx Ant. 2-2 -2 -.5 - -.5.5.5 2 2 Rx Ant. 2.5 h 2,.5.5 -.5 h 2,2 -.5 - - -.5 -.5 -.5 - -.5.5.5-2 -2 -.5 - -.5.5.5 2. MIMO SM QPSK/6QAM Fig.. QPSK/6QAM signal constellations from transmitted and received antennas when channel correlation, θ = 3 with pre-coder
(JBE Vol. 2, No., January 25) 3 Helsinki2. 8, 2x2 MIMO, [5]. 3. Table 3. Power delay profile of outdoor channel Number of tap Delay[us] Gain[dB] -4. 2.94-7.5 3.288-9.5 4.694-5.9-5 6 2.9-26 7 4.9-3 8 8.9-3 SM SM - SM BER., = 3, 6QAM QPSK 2 ( /3). 4/9 SM, SM, - SM BER. SM SM, -SM., - SM SM -4 SNR.2 db., 2 2/3 SM, SM, - SM BER. SM SM - SM -4 SNR. db,.4 db. DVB-T2 FFT 4K, /4, QPSK, 6QAM., FFT 32K, /32, 64QAM, 256QAM -2 Conventional SM Precoded SM UP-Precoded SM Average Coded BER -3-4 -5 6.4 6.6 6.8 7 7.2 7.4 7.6 7.8 8 8.2 8.4 SNR [db]. SM, SM, - SM (code rate = 4/9) Fig.. Performances of average coded BER for conventional SM, precoded SM and UP-precoded SM (code rate = 4/9)
-2 Conventional SM Precoded SM UP-Precoded SM Average Coded BER -3-4 -5.2.4.6.8.2.4.6.8 2 2.2 SNR [db] 2. SM, SM, - SM (code rate = 2/3) Fig. 2. Performances of average coded BER for conventional SM, precoded SM and UP-precoded SM (code rate = 2/3) MIMO SM., 2., /,.. MIMO SM., 2x2 MIMO SM 2. SM QPSK 6QAM 3, QPSK 6QAM 2 SM SNR.2 ~.4 db. UHDTV (References) [] S. Ryu, S. K. Park, D. Oh, G. Sihn, K. Han, and S. Hwang, "Research activities on next-generation mobile communications and services in Korea," IEEE Commun. Mag., vol. 43, no. 9, pp. 22-3, Sep. 25. [2] E. Larsson, O. Edfors, F. Tufvesson, and T. Marzetta, "Massive MIMO for next generation wireless systems," IEEE Commun. Mag., vol. 52, no. 2, pp. 86-95, Feb. 24. [3] J. Paulraj, D. A. Gore, R. U. Nabar, and H. B olcskei, "An overview of MIMO communications: A key to gigabit wireless," Proc. IEEE, vol. 92, no. 2, pp. 98-28, Feb. 24. [4] L. Vangelista, N. Benvenuto, S. Tomasin, C. Nokes, J. Stott, A. Filippi, M. Vlot, V. Mignone, and A. Morello, "Key technologies for next-generation terrestrial digital television standard DVB-T2," IEEE Commun. Mag., vol. 47, no., pp. 46-53, Oct. 29. [5] Frame structure channel coding and modulation for a second generation digital terrestrial television broadcasting system (DVB-T2), ETSI EN 32 755, v.2., Oct. 2.
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- 987 : - 989 : KAIST - 993 : KAIST - 987 ~ 996 8 : - 996 8 ~ : IT - 26 7 ~ 28 7 : TV/ - 2 ~ : IT - ORCID : http://orcid.org/-2-7769-236 - :,