1) what is meant by hopping sequence? The total available bandwidth is split into many channels of smaller bandwidth.Transmitters and receivers stay on one of thesechannels for a certain time and the hop(change) to another channel.The pattern of channel usage is called hopping sequence. Two types of hopping sequence : slow hopping and fast hopping. 2)compare SDMA and TDMA? SDMA:Constitute the infrastructure implementing SDM.Used for allocating seperate space to users in wireless network.Segment space into sectors use directed antennas. Adv:very simple,Increases capacity per km square. Disadv:Inflexible,Antennas typically fixed. TDMA:Comprises of all techniques that allocate certain time slots for communication.Continuous transmission is not required because users do not use the allocated bandwidth all the time. ADV:Established,Fully Digital,very flexible Disadv:Inflexible,Frequencies are a scarce resource. 3)Frequency range of uplink and downlink in GSM nw? GSM stands for Global System for Mobile Communications. GSM 900: Uplink-890-915 MHz Downlink-935-960 MHz GSM 1800:Uplink-1710-1785 MHz Downlink-1805-1880 GSM 1900:Uplink-1850-1910 MHz Downlink-1930-1990 MHz 4)What is hard handover and soft handover in GSM? When performing handover from one cell(network) to another cell,first the station terminates its connection in its own network and then connected to another network is called hard handover. When performing handover from one cell to another,first a station establish connection from its own network to another and then terminates the connection from its own network is called soft handover. 5)What is HIPERLAN? HIPERLAN-High Performance Local Area Network.. key feature is time sensitive data services.Innovative feature is ability to forward data packets through relays. 4 types: HIPERLAN 1,HIPERLAN 2,HIPERLAN 3(HIPER ACCESS),HIPERLAN 4(HIPERLINK). 6) characteristics of adhoc Instant infrastructure Disaster relief Remote areas Effectiveness 7)Binding in mobile IP Optimization of a route can be done by informing the correspondent node about the current location of mobile node.For this,the mobile IP protocol needs 4 additional messages. binding request binding update binding acknowledgement binding warning 8)hybrid routing protocol. The example of hybrid routing protocol is Zone Routing Protocol.It is the combination of proactive and reactive routing. within a Zone=>Proactive in nature Outside a zone=>Reactive in nature Adv:Reduce routing tables,one or more node representation,router for all traffic to/from cluster. 9)Functions of wTP: Provides reliable message transfer mechanisms based on request/reply paradigm. Based on ideas from TCP/RPC. provides peer to peer,client/server and multicast applications. Supports concatenation of PDUs,Header compression,flow control,retransmission of lost packet,user acknowledgement option. 10)advantages of wml over http: Limited display Navigation capability devices Hiperlinks and navigation support Data input Screen management
Posted on: Tue, 22 Oct 2013 00:42:08 +0000