Here I write on article How Wimax works and on wimax terminology
Here I write in short Advantages and disadvantages of Multicast Forwarding. Multicast Routing is backwards from Unicast Routing Unicast Routing is concerned about where the packet is going or will need to go. Multicast Routing is concerned about where the packet came from or will be coming from. Multicast Routing uses “Reverse Path Forwarding” (RPF) … Read more
If a mobile device moves to a new network and keeps the same IP address, the address will not reflect its new location therefore routers will be unable to route datagram to it correctly (or at all). Alternatively, if a mobile device moves to a new network and gets allocated a new address, already established … Read more
DHCP – Dynamic Host Configuration Protocol DHCP server is configured with a range of addresses Host 3 boots up and enters Initialize state It broadcasts a DHCP Discover message Then enters Select state DHCP servers send DHCP offer message Host 3 sends a DHCP request to one of the servers Host 3 enters the Request … Read more
There are two ways to transmit training symbols: preamble or pilot tones. Preambles entail sending a certain number of training symbols prior to the user data symbols. In the case of OFDM, one or two preamble OFDM symbols are typical. Pilot tones involve inserting a few known pilot symbols among the subcarriers. Channel estimation in … Read more
Set of modulation/coding schemes QPSK, 16QAM, 64QAM distributed over one sector: SINR distribution automatic selection mechanisms Maximum throughput per sector Highest modulation scheme Lowest coding protection Mean throughput offered per sector Contribution of different modulations Average over the area AMC is a link adoption (LA) method to adapt the transmission parameters to take advantage of … Read more
Data bits modulate (modify) a carrier signal Basic modulation techniques: amplitude frequency phase. Data bits are represented over the transmission channel by SYMBOLS Symbol rate is expressed in Baud (Symbols per Second) Modulation of a carrier is used to transmit data bits efficiently over the air interface The modulation process creates modulation symbols. A modulation … Read more
Here I list out some important OFDM characters for Wimax. Let’s check it in detail. OFDM Pros and Cons: OFDM enjoys several advantages over other solutions for high-speed transmission. Reduced computational complexity: OFDM can be easily implemented using FFT/IFFT and the processing requirements grow only slightly faster than linearly with data rate or bandwidth The … Read more
Orthogonal frequency division multiple access (OFDMA): Mobile WiMAX uses OFDM as a multiple-access technique, whereby different users can be allocated different subsets of the OFDM tones. As discussed in detail in Chapter 6, OFDMA facilitates the exploitation of frequency diversity and multiuser diversity to significantly improve the system capacity. Flexible and dynamic per user resource … Read more
The challenge to broadband wireless comes from the scarcity of radio-spectrum resources. Regulatory bodies around the world have allocated only a limited amount of spectrum for commercial use. The need to accommodate an ever-increasing number of users and offering bandwidth-rich applications using a limited spectrum challenges the system designer to continuously search for solutions that … Read more
Applications using a fixed wireless solution can be classified as point-to-point or point-to-multipoint. Point-to-point applications include interbuilding connectivity within a campus and microwave backhaul. Point-to-multipoint applications include broadband for residential, small office/home office (SOHO), and small- to medium-enterprise (SME) markets, T1 or fractional T1-like services to businesses, and (3) wireless backhaul for Wi-Fi hotspots. Consumer … Read more