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SDMA Techniques For Wireless ATM
Presented by
Biswajita Das Roll # EC200157151
Under the Guidance of
Mr. N. Srinivasu
Introduction
What is SDMA?
What is ATM?
Why SDMA technique is used in WATM?
The following system functions show performance of SDMA techniques in WATM:-
Spatial dimension
Medium access control
Space-time scheduling
Random access
Performance evaluation
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[attachment=15329]
SDMA Techniques For Wireless ATM
Introduction
What is SDMA?
What is ATM?
Why SDMA technique is used in WATM?
SDMA Techniques in WATM
The following system functions show performance of SDMA techniques in WATM:-
Spatial dimension
Medium access control
Space-time scheduling
Random access
Performance evaluation
Spatial Dimension
The deployment of a smart array antenna with several antenna elements form spatial dimension within single radio cell and permits the use of SDMA techniques.
This access technique allows different users to be served on same frequency channel at the same time.
Two types spatial signal processing algorithm are required to enable SDMA:
Spatial filtering algorithm
Beam forming algorithm
Figure 9.1 Simultaneous transmission using directive beams.
The task of a MAC protocol is to coordinate the access of MTs to the shared radio channel.
MAC protocol uses the following transport channel:-
BCH
FCH
RCH-P
RCH-UP
Access feedback channel
Short channel
Long channel
Transmission of MAC Protocol
HIPERLAN/2 MAC protocol provides two methods for transmission of messages to the base station on the uplink:
Explicit signaling using the SCH
Random access using the RCH
At end of each MAC frame the scheduler updates its information database about the terminal’s capacity demands by evaluating the received messages.
SPACE-TIME SCHEDULING
Space-time scheduling is an algorithm by which scheduler determines temporal transmission sequence of MAC PDUs as well as the MTs that can simultaneously be addressed to concurrently transmit their bursts.
It is of two type:-
Uplink Scheduling
Downlink Scheduling
The algorithm determines the transmission & reception schedule obeying the agreed-upon QoS requirements.
Random Access
In HIPERLAN/2, MTs can access the RCH to transmit their resource request message to base station.
Especially for delay-sensitive services, this access should be carried out as fast as possible, that is, the collision resolution algorithm has to be optimized for short delays.
HIPERLAN/2 facilitates the task of fast collision resolution by broadcasting the outcome of random access via the ACH of next frame.
Performance Evaluation
Here evaluation of application of SDMA technique is shown.
The table-1 gives the expectation Ek[X] of the number of MAC PDUs successfully received by the base station on the uplink.
The number of MTs allowed to transmit their bursts simultaneously has been set to k and the MT positions have been chosen at random within the coverage area of the base station antenna.
The number of successfully received bursts slightly increases for more than four MTs, for more than six MTs the values are decreased.
Conclusion
In this report we discussed SDMA techniques for WATM embedded in HIPERLAN/2.
Based on the enhanced signal processing capabilities, it is shown how the HIPERLAN/2 MAC protocol can be extended to the spatial domain for the up- and downlink.
Some basic ideas for scheduling algorithm have been described which aim at effective usage of joint TDMA-SDMA scheme, while preserving agreed-upon QoS requirements.
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PLS gv me more information of how to apply SDMA in WATM
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to get information about the topic"SDMA Techniques For Wireless ATM" refer the page link bellow
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