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Tutorial 8 Mohamed Esam Mobile Communications. 6 1 3 5 7 2 4 Omni Cell planning 6 1 3 5 7 2 4 120 Sectorization 6 3 5 7 2 4 1 60 Sectorization 8 10 1.

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Presentation on theme: "Tutorial 8 Mohamed Esam Mobile Communications. 6 1 3 5 7 2 4 Omni Cell planning 6 1 3 5 7 2 4 120 Sectorization 6 3 5 7 2 4 1 60 Sectorization 8 10 1."— Presentation transcript:

1 Tutorial 8 Mohamed Esam Mobile Communications

2 6 1 3 5 7 2 4 Omni Cell planning 6 1 3 5 7 2 4 120 Sectorization 6 3 5 7 2 4 1 60 Sectorization 8 10 1 7 2 3 4 9 6 12 5 11 (Most Common) Tricell planning: (Most Common) No. of cells in the cluster can be divided by 3

3 Tricell planning D1 D2 D3 C3 C2 C1 A3 A2 A1 B3 B2 B1 D1 D2 D3 C3 C2 C1 A3 A2 A1 B3 B2 B1 D1 D2 D3 C3 C2 C1 A3 A2 A1 B3 B2 B1 D1 D2 D3 C3 C2 C1 A3 A2 A1 B3 B2 B1 D1 D2 D3 C3 C2 C1 A3 A2 A1 B3 B2 B1 D1 D2 D3 C3 C2 C1 A3 A2 A1 B3 B2 B1 D1 D2 D3 C3 C2 C1 A3 A2 A1 B3 B2 B1 D1 D2 D3 C3 C2 C1 A3 A2 A1 B3 B2 B1

4 Prob.1 Construct 4 Walsh (Orthogonal) codes for 4 different users by two methods. Assume that 4 users transmit their data with 22Kbps (before spreading) using these codes such that: User 1 transmits +1 @ 500m User 2 transmits -1 @ 1000m User 3 transmits -1 @ 1200m User 4 transmits -1 @ 1500m Carrier Freq.=3GHz Path Loss Factor=2.

5 a) For downlink transmission, Construct the transmitted and decoded (de-spread) signals for the 4 users. Assuming users 1,2,3&4 see the following attenuation L 1 X, L 2 X, L 3 X and L 4 X; where Li is the path loss factor with (n=2) plus the following Noise Level; U1: +0.5p, U2: -1p, U3: +0.5p, U4:+1p. Find the decoded signals and calculate the average bit error rate based on X. Given that 0<X<1. c) X is the attenuation factor due to the shadowing effect with Standard deviation =32dB, Find the bit error rate (BER). d) If X has Rayleigh Fading distribution instead of the shadowing effect, Find the bit error rate (BER). e) Find the Average Duration of fade in Case (d) for 100km/hr vehicle.

6 L1 L2 L3 L4

7 1-a W1=0 W2= 0 0 0 1 -1 -1 -1 1 -1 -1 1 1 -1 1 1 -1 -1 -1 -1 1 -1 -1 1 1 -1 1 1 -1 -1 -1 -1 1 -1 -1 1 1 -1 1 1 -1 1 1 1 -1 1 1 -1 -1 1 -1 -1 1 W0=0000 W1=0101 W2=0011 W3=0110 W4= 0 0 0 0 0 1 0 1 0 0 1 1 0 1 1 0 W8=

8 *L1*X 1-a Wireless Channel U1 U2 U3 Data U4 Transmitted Signal (Air) -1 -1 -1 1 -1 -1 1 1 1 1 -1 -1 1 -1 1 1 -1 -1 1 -1 -1 1 2 -2 -2 -2 Transmitter (2 -2 -2 -2)*L 1 *X -1 1 1 -1 (2 -2 -2 -2)*L 2 *X (2 -2 -2 -2)*L 3 *X (2 -2 -2 -2)*L 4 *X *L2*X *L3*X *L4*X

9 +0.5p -1p +0.5p +1p Added Noise @ Rx (2 -2 -2 -2)*L 1 *X (2 -2 -2 -2)*L 2 *X (2 -2 -2 -2)*L 3 *X (2 -2 -2 -2)*L 4 *X (2L 1 X+0.5 -2L1X+0.5 -2L1X+0.5 -2L1X+0.5) (2L2X-1 -2L2X-1 -2L2X-1 -2L2X-1) -1 -1 -1 -1 -1 1 -1 1 -1 -1 1 1 -1 1 1 -1 (2L 3 X+0.5 -2L3X+0.5 -2L3X+0.5 -2L3X+0.5 ) (2L4X+1 -2L4X+1 -2L4X+1 -2L4X+1) (-2L 1 X-0.5 +2L1X-0.5 +2L1X-0.5 +2L1X-0.5) (-2L2X+1 -2L2X-1 +2L2X+1 -2L2X-1) (-2L 3 X-0.5 +2L3X-0.5 -2L3X+0.5 -2L3X+0.5) (-2L4X-1 -2L4X+1 -2L4X+1 +2L4X-1)

10 = +4L 1 X -2p “if ” >0  1 = -4L 2 X < 0  0 = -4L 3 X < 0  0 = -4L 4 X< 0  0 L 1 2 = L 2 2 = L 3 2 = L 4 2 = (-2L 1 X-0.5 +2L1X-0.5 +2L1X-0.5 +2L1X-0.5) (-2L2X+1 -2L2X-1 +2L2X+1 -2L2X-1) (-2L 3 X-0.5 +2L3X-0.5 -2L3X+0.5 -2L3X+0.5) (-2L4X-1 -2L4X+1 -2L4X+1 +2L4X+1)

11 X is the attenuation factor due to the shadowing effect with Standard deviation =27.5dB, Find the bit error rate (BER). = +4*253.3p X -2p if >0  1 = -4*63.3p X < 0  0 = -4*43.9p X < 0  0 = -4*28.14p X< 0  0

12 As 0<X (Attenuation) <1 is always positive; = +4*253.3p X -2p (NOT always >0  User1 sent: 1) = -4*63.3p X (always <0)  User2 sent: 0 = -4*43.9p X (always <0)  User3 sent: 0 = -4*28.14p X (always <0)  User4 sent: 0 Probability of Correct decoding is: Probability that X > 1.974*(10^-3) So: Probability that Loss <1/( 1.974*(10^-3)) So: Power Loss < 1/( 1.974*(10^-3))^2 or Power Loss < 54 dB

13 b-

14

15 c- If Rayleigh Fading is Considered instead of the shadowing effect,

16 D-

17 Autocorrelation (* then +) Pr.2 1111 Result 11110 11111 11112 11113 11114 11113 11112 11111 11110

18 Average voltage = 16/4= 4

19 Cross Correlation Pr.3 1111 Resul t 11 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 1 0 1 1 1 1 1 0

20 Average voltage = 0/4= 0

21 Rake Receiver It’s a well known block for CDMA receivers to eliminate multipath effect and increase SINR. Functions: Channel delay estimation or Impulse Response (IR) Measurement for multipath components Provides a separate correlation receiver for each of the multipath signals

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23 Mobile Network Generations 1 st Generation (1G): Many standards Analog System voice services only No SIM card Limited Roaming Examples in Table Other Standards: AMPS (USA) –Bell labs 1970 NTT (Japan) ARP NMT-900 In Use 19711986 Frequency Band 150 MHz900 MHz Channels 80400 Modulation FM Transmit Power 1  5W 100m, 1 and 6W Handover in Call NoYes Country FinlandSwitzerland Power Consumption highmedium

24 2 nd Generation (2G): 2 nd Generation (2G): Digital Voice Network Slow data rate (Short Message Service -SMS) Wider coverage compared to 1G Roaming support Circuit Switching GSM 900IS-95PDC In Use19911993 Frequency Band (Hz) 890  960M824  894M 810  1501M Channels / carrier 864 codes3 AccessTDMA / FDMA CDMA / FDMA TDMA / FDMA Transmit Power Up to 1W600 mW Handover in Call yes Countries Europe  212 countries (70% world) USAJapan Channel rate270.833 kbps1,228.8 kbps42 kbps Voice / data rate 13 / 9.6 kbps14.4 kbps6.7 kbps

25 2.5G: 2.5G: GSM  GPRS (General packet radio service): Released in 2001 <= 171.2Kbps/carrier Voice  Circuit switching, Data  Packet switching Media Message Service (MMS) IS-95  IS95B PDC  PDC-Data 2.75G 2.75G: GPRS  EDGE (Enhanced Data GSM Evolution): Released in 2003 <= 473.6 kbps/carrier Voice  Circuit switching, Data  Packet switching MMS and Internet access with better quality

26 3G: 3G: WCDMA (Wideband CDMA) = UMTS (Universal Mobile Telecommunications System): European CDMA/FDMA 1885-2025 MHz (uplink) and 2110-2200 MHZ (downlink) 384 kbps  Urban outdoor 2048 kbps  Indoor and low range outdoor Soft Handover (handover with same carrier) accommodate QoS classes for four types of traffic: Conversational class—Voice, video telephony, video gaming Streaming class— Multimedia, video on demand. Interactive class— Web browsing, network gaming, database access Background class—E-mail, short message service (SMS), file downloading Location Based services. CDMA2000 American

27 3.5G: UMTS-HSDPA (High Speed Downlink Packet Access) 2005/06 3.5G: UMTS-HSDPA (High Speed Downlink Packet Access) 2005/06 Decreasing delay due to transmission errors  Hybrid Automatic Repeat Request. Decreasing Handover failure  Fast cell site selection. Improving resources management  Stand alone downlink shared channel Adaptive Modulation and Coding. Download up to(14.4 Mbps and Upload up to 384 kbps) /sector. 3.75G: UMTS- HSUPA (High Speed Uplink Packet Access) 2007/08 3.75G: UMTS- HSUPA (High Speed Uplink Packet Access) 2007/08 DL: 14.400Mbps and UL: 5.8Mbps

28 4G: “in Research” 4G: “in Research” Toward 100Mbps with IP core network Toward 100Mbps with IP core network WiMAX Long Term Evolution (LTE)

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30 References Tommi Heikkilä; S-72.333 Postgraduate Course in Radio Communications


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