1. by P. Sriploy, M. Uthansakul and R. Wongsan
Investigation into GPRS Transmission Employing Switched Beam Antenna at Mobile Station
by P. Sriploy, M. Uthansakul and R. Wongsan

2. Outline Introduction GPRS Transmission Simulation Conclusion
Background
GPRS System
Smart Antenna System
Literature Survey motivation
GPRS Transmission
Simulation
Assumption
Results
Conclusion
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3. Introduction
GPRS (General Package Radio Service) is a packet oriented Mobile Data Service available to users of Global System for Mobile Communications (GSM)
Quality of GPRS transmission  Coding Scheme (CS)
Smart antenna system is envisaged to improve the quality of GPRS transmission
Coding Scheme
C/I
Datarate (kbps)
CS -1
less than 7
9.05
CS -2
7 – 12
13.4
CS -3
15.6
CS -4
more than 17
21.4
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4. Introduction Smart antenna system = array antenna
+ signal processing unit
Benefits
better range/coverage
greater battery life
smaller/lighter handset size
increased capacity
multipath rejection
reduced expense
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5. Introduction 2 types of smart antenna system: - Switched beam antenna
- Adaptive antenna
- Switched beam antenna performs similarly
to adaptive antenna when employing few antenna
elements [5]
- Switched beam antenna outperforms adaptive antenna when
the desired signal is not sufficiently larger than interferences [5]
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6. Introduction Literatures For this paper:
Concept of smart antenna has been proposed at Base Station to enhance GPRS transmission [6]
This results in high cost and complexity
For this paper:
We propose the idea of using switched beam antenna at Mobile Station to enhance the quality of GPRS transmission
Effect of array size reduction on the system throughput is also investigated
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7. GPRS Transmission PL GPRS Parameter Path Loss TDMA/FDD
Reverse Channel: 890 – 915 MHz
Forward Channel: 935 – 960 MHz
Channel Bandwidth: 200 kHz
Duplex Separation: 45 MHz or 3 Time Slots
Total Number of RF Duplex Channel: 124 users
Path Loss
(Fading)
(No Fading)
received power
transmitted power
antenna gain at BS
antenna gain at user PL
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8. Computer Simulation Assumption - 100 users  uniformly distributed
- Antenna gain:
switched beam; 6.76 dB
omnidirectional; 0 dB
at BS; 14 dB
- Mutual coupling effect between the array elements is included
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9. Simulation Results
Average C/I (dB)
- Omnidirectional = 7.22
- 0.1λ = 7.45
- 0.2λ = 8.25
- 0.3λ = 11.10
- 0.4λ = 12.95
- 0.5λ = 15.23
switched beam
- Switched beam antenna provides better performance compared with omni-
directional antenna
- Best C/I is obtained from the case when the array antenna is spaced by 0.5λ
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10. Simulation Results
Average throughput (dB)
- Omnidirectional = 11.22
- 0.1λ = 11.26
- 0.2λ = 12.45
- 0.3λ = 14.44
- 0.4λ = 14.83
- 0.5λ = 16.56
switched beam
Switched beam antenna provides better throughput, specially
when we utilize the array having inter-element spacing of 0.5λ
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11. Simulation Results
40%
13%
System throughput decreases as the array spacing is reduced
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12. Conclusion
Utilizing switched beam antenna at Mobile Station enhances the performance of GPRS system
Array elements spaced by 0.5λ provides the best performance
Array spacing reduction affects the system C/I and throughput
Ones can find the provided information useful for designing a switched beam antenna for GPRS system
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13. End
Thank you for attention!!
Question?
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