Terminologies in Wireless Communication Group Members Munib Ahmed Rehan Khan

Evaluation of Mobile Technologies

Mobile Technologies comparison

IEEE wireless Standards TechnologyIEEE StandardsSpeedBand WiFI a/b/gb: 11 to g: 54 Mbps4.5GHz -5GHz Bluetooth Up to 1Mbps4GHz Zig-Bee kbps950MHz-2.4MHz WiMax Mbps2-11GHz Mobile-Fi Mbit/s.below 3.5 GHz

Modulation Analog Modulation FM o Varying the frequency of the carrier wave on which useful information is imposed or impressed upon. AM o Amplitude of the carrier wave is varied in proportion to that of the message signal being transmitted PM o encodes a message signal as variations in the instantaneous phase of a carrier wave.

Digital Modulation Amplitude shift keying(ASK) Amplitude Modulation which represents the binary data in the form of variations in the amplitude of a signal. Frequency shift keying(FSK) frequency of the carrier signal varies according to the digital signal changes Phase shift keying(PSK) digital modulation process which conveys data by changing (modulating) the phase of a constant frequency reference signal (the carrier wave).

Digital Modulation Quadrature Phase Shift Keying (QPSK) form of Phase Shift Keying in which two bits are modulated at once, selecting one of four possible carrier phase shifts (0, 90, 180, or 270 degrees). Binary Phase Shift Keying (BPSK) two phase modulation scheme, where the 0’s and 1’s in a binary message are represented by two different phase states in the carrier signal: θ=0 ∘ for binary 1 and θ=180 ∘ for binary 0.

Multiplexing Frequency division multiplexing (FDM) Multiple data transmitted in different frequency slots slots Time division multiplexing (TDM) Multiple data transmission in different time slots

Multiplexing CDMA Allow many user to share the same bandwidth

Frequency Spectrum Spread Spectrum Spread spectrum is a form of wireless communications in which the frequency of the transmitted signal is deliberately varied Frequency hopping spread spectrum(FHSS)

Frequency Spectrum direct sequence spread spectrum(DSSS) Spreading code frequency reuse process of using the same radio frequencies on radio transmitter sites within a geographic area that are separated by sufficient distance to cause minimal interference

Wireless channel Fading large-scale fading o loss of signal as a function of distance and shadowing by large objects such as buildings and hills. Small scale fading o due to the constructive and destructive interference of the multiple signal paths between the transmitter and receiver. Also called multi path fading

Wireless channel Uplink o wireless link from the users to a base-station is called the uplink or a reverse channel. Downlink o wireless link from a base-station to the mobile users is called the downlink or the forward channel Forward link o the communication from the base-station to the mobile users, called the forward link

Wireless channel Channel Estimation Channel equalization

Wireless channel Line of Sight (LOS) o type of propagation that can transmit and receive data only where transmit and receive stations are in view of each other without any sort of an obstacle between them. Free Space Loss (FSL) o loss in signal strength of a signal as it travels through free space. This value is usually calculated by discounting any obstacles or reflections that might occur in its path

Wireless channel Doppler shift o when the transmitter of a signal is moving in relation to the receiver. The relative movement shifts the frequency of the signal, making it different at the receiver than at the transmitter Diversity o to improve the performance over a fading radio channel with multiple copies of the same information signal which are transmitted over two or more real or virtual communication channels

Wireless channel MIMO channel o technique for sending and receiving more than one data signal simultaneously over the same radio channel by exploiting multipath propagation. Shadowing o shadowing is deviation of the power of the received electromagnetic signal from an average value Ray- Tracing o received waveform can be approximated by the sum of the free space wave from the transmitter plus the reflected free space waves from each of the reflecting obstacles.

Wireless communication systems Cellular communication Public switched telephone network (PSTN) o These networks provide the infrastructure and the services for public telecommunication(LAND LINE). Base station(MBS) connected to an antenna (or multiple antennae) that receives and transmits the signals in the cellular network to customer phones and cellular devices MSC (Mobile Switching Center) o The MSC is mostly associated with communications switching functions, such as call set-up, release, and routing. Soft Handoff(make before brake), hard handoff(break before make)

Wireless communication systems Antenna Side lobe Lobe that is not part of main lobe(local Maxima) Bandwidth the range of frequencies over which the antenna can properly radiate or receive energy Beamwidth Beam width is the area where most of the power is radiated, which is the peak power. SNR Ratio of signal power to noise at receiving end

Wireless communication systems Cellular digital packet data (CDPD) CDPD support make it possible for mobile users to get access to the Internet at up to 19.2 Kbps. Paging Systems wireless communication systems that are designed to send brief messages to a subscriber,a one-way messaging system in which Base Station send messages to all subscribers.

Wireless network terminology SSID(Service Set Identifier) Name associated with wireless local area network (WLAN) including home networks and public hotspots client An application on a computer or device connected to a network that requests services (files, print capability) from another connected computer or device on the network Infrastructure mode A client setting for a local area network that allows devices connected to the network to communicate with one another through a central access point or router. Ad-hoc wireless connection having no infrastructure(independent of an access point or router)

Wireless network terminology Dual-band Wireless routers that provide offer both 2.4 GHz and 5.0 GHz ranges are called a dual-band. Firewall router provide added layer of Internet security, called a Firewall that is very important for home networks. Broadband Another name for high-speed Internet at wider area(DSL,Fiber,satellite) Access point (AP) wireless network transceiver or "base station" hub, often used to connect a local area network to one or more wireless devices

Wireless network security IP address WEP(Wired Equivalent Privacy) 40-bit (also called 64-bit), or in 108-bit (also called 128-bit) encryption code for wireless data privacy WEP key WEP key with 10 or 23 characters can include numbers and the letters A - F, and are not case-sensitive(text string) DNS Google.com 

Wireless network security WPA(Wi-Fi Protected Access) high level of wireless network security. Using data encryption through the Temporal Key Integrity Protocol (TKIP). WPA-PSK Wi-Fi Protected Access Pre-Shared Key (WPA-PSK) is a security mechanism used to authenticate and validate users on a wireless LAN (WLAN) or Wi-Fi