Design of Antennas for Handheld DVB-H ... - Lunds tekniska högskola

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13.27 Mbit/s is assigned to DVB-H services whereas the remaining capacity is shared between ordinary DVB-T services. This example shows that it is possible to transmit both DVB-T and DVB-H within the same network. Another benefit with time slicing is that the receiver is able to search for the service in use in other cells during the receiver’s off time. In this way a channel handover can be performed at the border between two cells without the user knowing anything about it [6]. Figure 2.4. An example of the data sent trough one multiplexer. 2.1.5.3 Multi Protocol Encapsulation – Forward Error Correction Handheld devices with small antennas make the reception of high data rate streams in mobile environment unreliable and difficult. Because of that Multi Protocol Encapsulation – Forward Error Correction (MPE-FEC) was added to the DVB-H standard to improve the C/N- and Doppler performance in mobile channels and to improve the tolerance against impulse interference [16]. The use of MPE-FEC is optional. In contrast to other DVB transmission systems based on the DVB transport stream adopted from the MPEG-2 standard, the DVB-H system is based on Internet Protocol (IP). Therefore is the base-band interface an IP interface, this interface allows the DVB-H system to be combined with other IP networks. The MPEG-2 transport stream is still used, because the IP data are embedded into the transport stream by means of the Multi Protocol Encapsulation (MPE), a protocol defined by DVB Data Broadcast Specification. On the same level as MPE is an additional Forward Error Correction (FEC) added. This technique is called MPE-FEC and is the second main innovation besides time slicing [15]. Intensive testing of DVB-H, by DVB member companies showed that use of MPE-FEC improves the result by 7 dB over DVB-T [12]. The MPE-FEC scheme is located on the link layer at the level of input IP streams before they are encapsulated by means of the MPE. The MPE, MPE-FEC and time slicing techniques are neighboring in the transmitter block diagram (See 12
figure 2.5). All three elements together form the DVB-H codec, which contain the essential DVB-H functionality. The input IP streams coming from different sources as single elementary streams are multiplexed one by one according to the time slicing method. The MPE-FEC error protection is calculated and added separately for each single elementary stream before they are encapsulated into the transport stream. All data processing is carried out before the transport stream interface to guarantee compatibility to a DVB-T transmission network [15, 30]. 2.1.5.4 MPE-FEC frame Figure 2.5. The three elements that form the DVB-H codec. The MPE-FEC scheme consists of RS code in conjunction with a block interleaver. The MPE-FEC encoder creates a specific MPE-FEC frame (See figure 2.6). In that frame are all DVB-H coded input data inserted. The frame consists of 255 columns and a maximum of 1024 rows and with every cell equivalent to one byte, the maximum frame size is almost 2 Mbit. A frame is divided in two parts, the application data table and the RS data table. The application data table is the 191 columns to the left and is filled with the IP packets of the service to be protected. The first byte of the first datagram inserts in the upper left cell and going downwards the first column. If a datagram is longer than a column it continues on top of the next column. With the application data table filled with datagrams or zero padding it is possible to calculate the 64 Parity bytes in the RS data table for each row with RS (255,191) code. When the application data table is filled with IP packets and RS data table with parity bits the MPE-FEC frame is ready for transmission [17]. The IP packets are read out of the application data table and encapsulated in IP sections by means of the MPE method. The IP data is carried in MPE sections irrespective MPE-FEC is used or not. This makes reception backwards compatible with MPE-FEC ignorant receiver. 13
Page 1 and 2: Design of Antennas for Handheld DVB
Page 3 and 4: Acknowledgements This master thesis
Page 5 and 6: 4 DESIGN AND TESTING OF ANTENNA SOL
Page 7 and 8: Figure 5.2. Reference dipole antenn
Page 9 and 10: 1 Introduction The passed decade th
Page 11 and 12: 2 Background This chapter provides
Page 13 and 14: is simultaneously modulated into 10
Page 15 and 16: 2.1.3 Reed-Solomon Codes 2.1.4 DVB-
Page 17 and 18: 2.1.5 DVB-H DVB-H is the latest dev
Page 19: 2.1.5.2 Time slicing A large proble
Page 23 and 24: symbols or four 2K OFDM symbols. Th
Page 25 and 26: 2.2 Competing standards The DVB-H s
Page 27 and 28: 2.3 Antenna theory This section des
Page 29 and 30: Figure 2.9. Impedance bandwidth def
Page 31 and 32: unloaded quality factor (Q0) and th
Page 33 and 34: losses should be avoided in handhel
Page 35 and 36: 3.3 Loop Figure 3.1. Yagi-Uda anten
Page 37 and 38: PIFA Figure 3.2. Four different con
Page 39 and 40: The size of the antenna is another
Page 41 and 42: 4.4 PIFA To verify the balun a resi
Page 43 and 44: 4.5 Folded-Patch With the PIFA-ante
Page 45 and 46: Figure 4.9a. Folded-patch 2, front
Page 47 and 48: Figure 4.11. Loop antenna schematic
Page 49 and 50: Figure 4.15. Wire loop antenna retu
Page 51 and 52: using an H-field antenna together w
Page 53 and 54: antenna. The dimension of the anten
Page 55 and 56: The result of the return loss measu
Page 57 and 58: Figure 4.24. Return loss graph for
Page 59 and 60: The result of the measurement of th
Page 61 and 62: Figure 4.31. Return loss graph for
Page 63 and 64: frequency band, the first from 470
Page 65 and 66: Figure 5.6. Radiation pattern for R
Page 67 and 68: 5.1.3 Measurement result In this ch
Page 69 and 70: Figure 5.10. Radiation pattern for
Page 71 and 72:
Figure 5.12. Radiation pattern for
Page 73 and 74:
Table 5.4. Switched monopole 1, gai
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Power gain / dB 2 0 -2 -4 -6 -8 -10
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Figure 5.22. Radiation pattern for
Page 79 and 80:
was received in all five channels.
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6.3 Control signal 6.4 Cost The swi
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not be possible, there will always
Page 85 and 86:
There are many advantages with tuna
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8 References [1] Schiller, Jochen -
Page 89:
[29] Gardiol, Fred - Microstrip cir
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Design of Antennas for Handheld DVB-H ... - Lunds tekniska högskola

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