DESIGNING OF WIFI MAC TRANSMITTER

USING VHDL

BATCH NO: A4

INTERNAL GUIDEK.CHIDAMBARA RAO Assoc.ProfessorDept. of ECE

Presented by:B.RASAZNA (08A51A0417)G.SRIRAM (08A51A0441) I.SIVAJI (08A51A0444)D.PRIYANKA (08A51A0426) B.SRINU (08A51A0418)

•The main objective is to design and implementation WIFI MAC Transmitter using VHDL.

•For the wireless communication in RF range IEEE 802.11 is one of the many standards available .

•IEEE 802.11b defines the Medium Access Control Layer for wire less local area networks.

Abstract

• Wi-Fi MAC transmitter module is divided into 5 blocks I.e.. data unit interface block, controller block, payload data storage block, MAC header register block, data processing block.

• In this project, we are considering only two blocks i.e. payload data storage block, data processing block

Introduction to WIFI

• Wireless Technology is an alternative to Wired Technology, which is commonly used, for connecting devices in wireless mode.

• Wi-Fi (Wireless Fidelity) is a generic term that refers to the IEEE 802.11 communications standard for Wireless Local Area Networks (WLANs).

• Wi-Fi Network connect computers to each other, to the internet and to the wired network.

IEEE 802.11 Architecture

Standard 802.11b 802.11a 802.11g

Speed 11 Mbps 54 Mbps 54Mbps

Range 100-150 feet indoors 27-75 feet indoors 100-150 feet indoors

Frequency 2.4GHz, a band

already crowded with

cordless phones

5GHz, an un crowded

band

2.4GHz, still a crowd

of cordless phones

and microwaves

Acceptance Hot spots are already

established using

802.11b. Equipment is

readily available

More common in

corporate and office

environments.

802.11g is compatible

with the specs for

802.11b, meaning it

can be used on a

network based on b

or g versions.

Elements of a WI-FI Network

• Access Point (AP) - The AP is a wireless LAN transceiver or “base station” that can connect one or many wireless devices simultaneously to the Internet.

• Wi-Fi cards - They accept the wireless signal and relay information. They can be internal and external.(e.g. PCMCIA Card for Laptop and PCI Card for Desktop PC)

• Safeguards - Firewalls and anti-virus software protect networks from uninvited users and keep information secure.

WIFI MAC TRANSMITTER BLOCK DIAGRAM

Explanation:

The architecture contains five blocks1.MAC Header2.Data unit interface block3.Data Processing block4.Pay Load Data storage block5.Controller block

• MAC Header:

• Frame control Field: It controls flow of frames.

• Duration /ID: The Duration ID is 16 bits length. It carries the association identity of the station that transmitted the frame .

• Address1: Always receiver address (i.e. the station on the BSS who is the immediate receiver of the packet).

• Data unit interface block: It is to interface all the blocks in the architecture.

• Control Block: It control the functioning of all the blocks in the architecture.

• Pay Load Storage Block:It further divided into two blocks FIFO Data Length Counter

• FIFO:

It contains the data to be transmitted. It acts as the synchronizing tool .

FIFO

Sys clk

Sys rst

Data in

FIFO ENA

FIFO Data

FULL

EMPTY

• Data Lenth Counter:

Data length counter module acts as counter.it simply accepts a Max Number and counts the data being transmitted .

DatLen cnt

clk

rst

dtaena

Max no

Dta cnt over

• Data processing Block:It is divided into three modules i.e. Serializer,HEC and CRC and

they are discussed in details as shown below

Serializer:

Various data selected at the multiplexer are serially obtained.

Serializer

clk

sysrst

srena

data

S bit

eoc

• HEC Module:

• This module produces the Head Error Check bits.• It is the 16-bit error check bit.the HEC is calculated when the

HRCCalEna is high

HEC

clk

rst

S bit

hEC calena

HEC out

HECover

• CRC Module:

Figure shows CRC module the CRC is 32bit field contain the 32 bit cyclic Redundancy check.

CRC

clk

rst

S bit

CRCout

CRC over

CRC calena

What is the scope of VHDL?

Why VHDL is used?

• Power and flexibility

• Devices- independent design

• ASIC Migration

• Benchmarking capability

• Quick Time-to-Market and low cost

ABOUT VHDL

ABOUT XILINX

Advantages• Mobility• Ease of Installation• Flexibility• Cost• Reliability• Security• Use unlicensed part of the radio spectrum• Speed• Low power consumption

Limitations

• Interference• Degradation in performance• Limited range

Conclusion

• Various individual modules of Wi-Fi Transmitter have been designed, verified functionally using VHDL -simulator, synthesized by the synthesis tool .

• This design of the WiFi transmitter is capable of transmitting the frame formats.

• The transmitter is also capable of generating errorchecking codes like HEC and CRC. It can handle variable data transfer