The Importance Of Multicarrier Techniques For A Single Carrier System

Inter symbol interference (ISI) is avoided by assuming the duration of cyclic long enough and furthermore the channel is assumed to be stationary within one symbol period ( h(k)=hr ).

4G networks offer 10 or more times the data transmission rate of a 3G network. The data rates available on a 4G network allow the cell phone to access information from the Internet as fast as a land-line connection.

Multicarrier modulation provides immunity to fading caused by data transmission over mul-tipath fading channels or frequency- selective fading channels. Each of the subchannel expe-riences flat fading due to the decreased bandwidth. Also, due to the increase in the symbol period, it provides enhanced immunity to ISI. Another advantage of multicarrier modulation technique is it can provide better spectral efficiency compared to single carrier modulation, since the spectrum of the subcarrier can be overlapped.

Cellular system divides the area into cells where mobile units are located and aims to increase the capacity of the channel with an efficient level of quality of service. Channel access can be achieved through: Frequency division multiple-access (FDMA), Time division multiple-access (TDMA), Code division multiple-access (CDMA), and Space Division Multiple access (SDMA). In this paper we will focus on SDMA systems.

4G LTE picks up pace – Fourth Generation Long Term Evolution networks are coming of age. Although this kind of high bandwidth network is in its infancy in many parts of the world, UK’s mobile operator EE is testing a network channel to reach 300 Mbps. Vodafone, Telefonica in Germany and SK Telecom of South Korea are testing channels to reach a speed of 225Mbps. Airtel first the first mobile phone operator in India to come up with the 4G LTE network.

A measure of quality of service in a wireless connection is made using SINR (Signal to noise interference ratio).For the performance evaluation let us consider a an overall network t to be composed of two-tier 19 macrocells, with many femtocells randomly deployed over the macrocells. Then the macro user would be interfered from neighbouring macro cell's (18) and all of the adjacent femtocells. Due to small transmit power, only femtocells which would be located in the 1-tier macrocell area gives interference to macro user. The estimation of the received SINR of a macro user m on subcarrier k, when the macro user is interfered from neighboring macrocells and all the adjacent Femtocells [12] would be given by where P_(M,K) and P_(M^1,K) is transmit power of serving macro-cell M and neighbouring macrocell M’ on subcarrier k, respectively. G_(M,m,K) is channel gain between macro user m and serving macrocell M on subcarrier k. Channel gain from neighbouring macro cells are denoted by G_(M1,m,K) Similarly, P_(F,K) is transmit power of neighbouring femtocell F on subcarrier k. .

The core technology of 4G is orthogonal frequency-division multiplexing (OFDM) which belongs to Multi-Carrier Modulation (MCM). It divides assigned channel into orthogonal sub channels, modulating and transmitting on each sub channel of narrowband (Aceña 2005). 3.2 Telecommunication system structure 3G is based on cellular network (shown in Figure 1), the core network of 3G is developed from GSM-MAP, AMPS and ANSI-41 which is the core network of GSM, the air interface and the corresponding system is backward 2G compatibility (Luo et al. 2003).

3G and 4G wireless networks can be compared and contrasted by four areas of capabilities: Service and application, network architecture, data throughput and user perception. “Some examples of services offered by 3G wireless networks are CDMA2000 (also known as IMT MultiCarrier (IMTMC), Universal Mobile Telecommunications System (UMTS), and EDGE as well as a long list of others while 4G offer Worldwide Interoperability for Microwave Access (Wimax2) and Long-Term Evolution (LTE- Advance).” (Jamia Yant, 2012, April 26) 3G applications allows users the ability to stream video and audio, video conferencing as well as other multi-media

In the field of telecommunications wireless communication is the most advanced and widely used method for long distance communication. Wireless Communication today faces various

LTE supports Frequency division duplex (FDD) and also time division duplex (TDD). TDD can is done for cases where cell size needs to be reduced significantly. We consider FDD here because it is widely used for implementation. However as number of users are increasing we will be going for TDD in the future. The technology is such developed that device may operate in TDD with one node and FDD with other node at the same time. For our case, we consider FDD as it is currently being used to a large extent.

This is to certify that the work titled “Progressive Image Transmission Using OFDM” submitted by “Aman Pandey(13102288) and Naman Gogia(13102216)” in partial fulfillment for the award of degree of Bachelor of Technology of Jaypee Institute of Information Technology, Noida has been carried out under my supervision. This work has not been submitted partially or wholly to any other University or Institute for the award of this or any other degree or diploma.

Mobile devices are getting smaller, lighter, and more powerful; they have bigger screens and longer battery life, more features and more capabilities .With the rapid growth of user demands, and the limitations of third generation (3G) mobile communication systems, it is expected that fourth generation (4G) mobile systems are likely to reach the consumer market in another 4-5 years. 4G systems are expected to become a platform capable of providing increased bandwidth, higher data rates, and greater interoperability across communication protocols, and user friendly, innovative, and secure applications. This system will primarily focus on seamlessly integrating the existing systems like GSM, wireless LAN, and Bluetooth. Since 4G is

The concentration of small cells in a network increases; measures need to be taken in order to ensure that the QoS is not degraded for the macrocell users as well as its nearest small cells. Interference managing in Heterogeneous Network in critical position .This is characteristically attained completed bright resource allocation schemes for small cells. In Heterogeneous Network, the mobile network is constructed with layers of small and large cells. This architecture is faced with the task of supply allocation (power, channel, time) for small cells in order to guarantee reliable and high quality service to both primary (macrocell) users as well as secondary (femtocell) users. In mobile network all users can be considered as nomadic, in the form of microcells, hot-spots, circulated antennas and relays becomes predictable. Therefore, for the deployment of the LTE systems the FAPs get a critical inspiring subject, mostly relating to the technical and business influences that it could signify and the method they could be combined efficiently into the LTE building.

Abstract – Conventional wireless communication schemes use radio/micro wave frequencies for data transmission, primarily because of the availability of high sensitivity receivers and ability to provide broad coverage at low frequencies and line of sight communication at high frequencies. But, RF can support only a limited bandwidth due to confined spectrum availability. Therefore the expanding demand for wireless data has led to clogging of the radio spectrum. Thus there is a need to study and use new communication technologies in near future that will reduce interference and will be a clean source of communication. Communication is providing new advances constantly, people are depending more and more on the benefits they provide.

The transmission frequencies of WiMAX technology from 2.3MHz to 3.5GHz to make it low price wireless network. WiMAX technology need different hardware infrastructure to transmit channel bandwidth. The bandwidth signal is separately in OFDMA or Orthogonal Frequency Division Multiplexed Access which is used to carry data called sub carrier. Transmitted data divided into numerous data stream where everyone is owed to another sub carrier and then transmitted at the same broadcast interval. At the downlink path the base station broadcast the data for different user professionally over uninterrupted sub-carriers.