ISSN 2319-8885 Vol.06,Issue.16 April-2017, Pages:3002-3007 www.ijsetr.com Adaptive Techniques in Advanced 4G Cellular Wireless Networks by using 8 * 8 Antennas 1 2 KAREEM MOHAMMED YASEEN AL.SAUDI , B.BHASKARA RAO 1PG Scholar, Acharya Nagarjuna University, Andhrapradesh, India, E-mail: [email protected]. 2Assistant Professor, Dept of ECE, Acharya Nagarjuna University, Andhrapradesh, India, E-mail:[email protected]. Abstract: The ability of 4G mobile wi-fi networks like long time Evolution advanced may be extended by means of large bandwidth for multicarrier operation, better quantity of antennas for extra spatial multiplexing, tighter reuse of radio cells the use of the same frequency spectrum and optimization of the community configuration in popular. The potentially better capability might be performed most effective if the entire wi-fi community can be more or less perfectly tailored to the current real environment at any time. This actual environment which incorporates as an example the radio channel, the user visitors, the gadget performance and the community configuration can exchange, but, inside a time scale of a wide variety from under 1 ms up to more than a hundred s. suitable linear or nonlinear adaptive strategies that are able to track those changes are defined for wideband linear power amplifier, a couple of input multiple(8*8) output antenna structures, heterogeneous networks and self- organising networks which includes the corresponding realisation and overall performance aspects. Keywords: Wireless Networks, Wi-Fi Community, GSM, GPRS, TDMA. I. INTRODUCTION the evolution of GSM to GPRS, using the same air interface A. LTE Overview and access method, TDMA (Time Division Multiple LTE (Long Term Evolution) or the E-UTRAN (Evolved Access). To reach higher data rates in UMTS (Universal Universal Terrestrial Access Network), introduced in 3GPP Mobile Terrestrial System) a new access technology R8, is the access part of the Evolved Packet System (EPS). WCDMA (Wideband Code Division Multiple Access) was The main requirements for the new access network are high developed. The access network in UMTS emulates a circuit spectral efficiency, high peak data rates, short round trip switched connection for real time services and a packet time as well as flexibility in frequency and bandwidth. switched connection for datacom services (black in figure 1). In UMTS the IP address is allocated to the UE when a datacom service is established and released when the service is released. Incoming datacom services are therefore still relying upon the circuit switched core for paging. The Evolved Packet System (EPS) is purely IP based. Both real time services and datacom services will be carried by the IP protocol. The IP address is allocated when the mobile is switched on and released when switched off. The new access solution, LTE, is based on OFDMA (Orthogonal Frequency Division Multiple Access) and in combination with higher order modulation (up to 64QAM), large bandwidths (up to 20 MHz) and spatial multiplexing in the downlink (up to 4x4) high data rates can be achieved. The highest theoretical peak data rate on the transport channel is 75 Mbpsin the uplink, and in the downlink, using spatial multiplexing, the rate can be as high as 300 Mbps. Figure1. Network Solutions from GSM to LTE. The LTE access network is simply a network of base GSM was developed to carry real time services, in a stations, evolved NodeB (eNB), generating a flat architecture circuit switched manner (blue in figure 1), with data services (figure 2). There is no centralized intelligent controller, and only possible over a circuit switched modem connection, the eNBs are normally inter-connected viathe X2-interface with very low data rates. The first step towards an IP based and towards the core network by the S1-interface (figure 2). packet switched (green in figure 1) solution was taken with Copyright @ 2017 IJSETR. All rights reserved. KAREEM MOHAMMED YASEEN AL.SAUDI, B. BHASKARA RAO The reason for distributing the intelligence amongst the 1 GHz. This bandwidth is divided up into 6-MHz wide base-stations in LTE is to speed up the connection set-up and channels. Initially, one TV station or channel used a single reduce the time required for a handover. For an end-user the 6-MHz band. But with digital techniques, multiple TV connection set-up time for a real time data session is in many channels may share a single band today thanks to cases crucial, especially in on-line gaming. The time for a compression and multiplexing techniques used in each handover is essential for real-time services where end-users channel. This technique is also used in fiber optic tend to end calls if the handover takes too long. communications systems. A single fiber optic cable has enormous bandwidth that can be subdivided to provide FDMA. Different data or information sources are each assigned a different light frequency for transmission. Light generally isn’t referred to by frequency but by its wavelength (λ). As a result, fiber optic FDMA is called wavelength division multiple access (WDMA) or just wavelength division multiplexing (WDM). One of the older FDMA systems is the original analog telephone system, which used a hierarchy of frequency multiplex techniques to put multiple telephone calls on single line. The analog 300-Hz to 3400-Hz voice signals were used to modulate subcarriers in 12 channels from 60 kHz to 108 kHz. Modulator/mixers created single sideband (SSB) signals, both upper and lower sidebands. These subcarriers were then further frequency multiplexed on subcarriers in the 312-kHz to 552-kHz range Figure2. X2 and S1 Interfaces. using the same modulation methods. At the receiving end of the system, the signals were sorted out and recovered with Another advantage with the distributed solution is that the filters and demodulators. Original aerospace telemetry MAC protocol layer, which is responsible for scheduling, is systems used an FDMA system to accommodate multiple represented only in the UE and in the base station leading to sensor data on a single radio channel. Early satellite systems fast communication and decisions between the eNB and the shared individual 36-MHz bandwidth transponders in the 4- UE. In UMTS the MAC protocol, and scheduling, is located GHz to 6-GHz range with multiple voice, video, or data in the controller and when HSDPA was introduced an signals via FDMA. Today, all of these applications use additional MAC sub-layer, responsible for HSPA scheduling TDMA digital techniques. was added in the NB. The scheduler is a key component for the achievement of a fast adjusted and efficiently utilized C. TDMA radio resource. The Transmission Time Interval (TTI) is set TDMA is a digital technique that divides a single channel to only 1ms. or band into time slots. Each time slot is used to transmit one byte or another digital segment of each signal in sequential B. FDMA serial data format. This technique works well with slow FDMA is the process of dividing one channel or voice data signals, but it’s also useful for compressed video bandwidth into multiple individual bands, each for use by a and other high-speed data. A good example is the widely single user (Fig3). Each individual band or channel is wide used T1 transmission system, which has been used for years enough to accommodate the signal spectra of the in the telecom industry. T1 lines carry up to 24 individual transmissions to be propagated. The data to be transmitted is voice telephone calls on a single line (Fig4). Each voice modulated on to each subcarrier, and all of them are linearly signal usually covers 300 Hz to 3000 Hz and is digitized at mixed together. an 8-kHz rate, which is just a bit more than the minimal Nyquist rate of two times the highest-frequency component needed to retain all the analog content. Fig3. The best example of this is the cable television system. Fig4. The medium is a single coax cable that is used to broadcast hundreds of channels of video/audio programming to homes. The digitized voice appears as individual serial bytes that The coax cable has a useful bandwidth from about 4 MHz to occur at a 64-kHz rate, and 24 of these bytes are interleaved, producing one T1 frame of data. The frame occurs at a International Journal of Scientific Engineering and Technology Research Volume.06, IssueNo.16, April-2017, Pages: 3002-3007 Adaptive Techniques in Advanced 4G Cellular Wireless Networks by using 8 * 8 Antennas 1.536-MHz rate (24 by 64 kHz) for a total of 192 bits. A signals can occupy the same channel simultaneously. For single synchronizing bit is added for timing purposes for an example, using 64 unique chipping codes allows up to 64 overall data rate of 1.544 Mbits/s. At the receiving end, the users to occupy the same 1.25-MHz channel at the same individual voice bytes are recovered at the 64-kHz rate and time. At the receiver, a correlating circuit finds and identifies passed through a digital-to-analog converter (DAC) that a specific caller’s code and recovers it. The third generation reproduces the analog voice. The basic GSM (Global System (3G) cell-phone technology called wideband CDMA of Mobile Communications) cellular phone system is (WCDMA) uses a similar method with compressed voice TDMA-based. It divides up the radio spectrum into 200-kHz and 3.84-Mbit/s chipping codes in a 5-MHz channel to allow bands and then uses time division techniques to put eight multiple users to share the same band. voice calls into one channel. Figure 3 shows one frame of a GSM TDMA signal.