Skip to main content

Posts

Challenges in the Migration to 4G

Second-generation (2G) mobile systems were very successful in the previous decade. Their success prompted the development of third generation (3G) mobile systems. While 2G systems such as GSM, IS-95, and cdmaOne were designed to carry speech and low-bit-rate data, 3G systems were designed to provide higher-data-rate services. During the evolution from 2G to 3G, a range of wireless systems, including GPRS, IMT-2000, Bluetooth, WLAN, and HiperLAN, have been developed. All these systems were designed independently, targeting different service types, data rates, and users. As all these systems have their own merits and shortcomings, there is no single system that is good enough to replace all the other technologies. Instead of putting efforts into developing new radio interfaces and technologies for 4G systems, which some researchers are doing, we believe establishing 4G systems that integrate existing and newly developed wireless systems is a more feasible option. Researchers are currentl...

MOBILE IPv6

Mobile IP is the IETF proposed standard solution for handling terminal mobility among IP subnets and was designed to allow a host to change its point of attachment transparently to an IP network. Mobile IP works at the network layer, influencing the routing of datagrams, and can easily handle mobility among different media (LAN, WLAN, dial-up links, wireless channels, etc.). Mobile IPv6 is a protocol being developed by the Mobile IP Working Group (abbreviated as MIP WG) of the IETF (Internet Engineering Task Force). The intention of Mobile IPv6 is to provide a functionality for handling the terminal, or node, mobility between IPv6 subnets. Thus, the protocol was designed to allow a node to change its point of attachment to the IP network such a way that the change does not affect the addressability and reachability of the node. Mobile IP was originally defined for IPv4, before IPv6 existed. MIPv6 is currently becoming a standard due to inherent advantages of IPv6 over IPv4 and will the...

Micro Electronic Pill

The invention of transistor enabled the first use of radiometry capsules, which used simple circuits for the internal study of the gastro-intestinal (GI) [1] tract. They couldn't be used as they could transmit only from a single channel and also due to the size of the components. They also suffered from poor reliability, low sensitivity and short lifetimes of the devices. This led to the application of single-channel telemetry capsules for the detection of disease and abnormalities in the GI tract where restricted area prevented the use of traditional endoscopy. They were later modified as they had the disadvantage of using laboratory type sensors such as the glass pH electrodes, resistance thermometers, etc. They were also of very large size. The later modification is similar to the above instrument but is smaller in size due to the application of existing semiconductor fabrication technologies. These technologies led to the formation of "MICROELECTRONIC PILL". Microelec...

Poly Fuse

Polyfuse is a new standard for circuit protection. It is resettable. Many manufacturers also call it polyswitch or multifuse. Polyfuses are not fuses but polymeric positive temperature co-efficient (PPTC) thermistors. Current limiting can be accomplished by using resistors , fuses , switches or positive temperature co-efficient devices. Resistors are rarely an acceptable solution because the high power resistors that are usually required are expensive. One-shot fuses can be used, but they might fatigue, and they must be replaced after a fault event. Ceramic PTC devices tends to have high resistance and power dissipation characteristics. The preferred solution is a PPTC device which has low resistance in normal operation and high resistance when exposed to a fault. Electrical shorts or electrically over-loaded circuits can cause over-current and over temperature damage. Like traditional fuses , PPTC devices limit the flow of dangerously high current during fault conditions. Unlike tradi...

Wearable Bio-Sensors

Wearable sensors and systems have evolved to the point that they can be considered ready for clinical application. The use of wearable monitoring devices that allow continuous or intermittent monitoring of physiological signals is critical for the advancement of both the diagnosis as well as treatment of diseases. Wearable systems are totally non-obtrusive devices that allow physicians to overcome the limitations of ambulatory technology and provide a response to the need for monitoring individuals over weeks or months. They typically rely on wireless miniature sensors enclosed in patches or bandages or in items that can be worn, such as ring or shirt. The data sets recorded using these systems are then processed to detect events predictive of possible worsening of the patient's clinical situations or they are explored to access the impact of clinical interventions. It is a pulse oximetry sensor that allows one to continuously monitor heart rate and oxygen saturation in a totally u...

4G Wireless Systems

Fourth generation wireless system is a packet switched wireless system with wide area coverage and high throughput. It is designed to be cost effective and to provide high spectral efficiency . The 4g wireless uses Orthogonal Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB),and Millimeter wireless. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr.The high performance is achieved by the use of long term channel prediction, in both time and frequency, scheduling among users and smart antennas combined with adaptive modulation and power control. Frequency band is 2-8 GHz. it gives the ability for world wide roaming to access cell anywhere. Wireless mobile communications systems are uniquely identified by "generation designations. Introduced in the early 1980s, first generation (1G) systems were marked by analog frequency modulation and used primarily for voice communications. Second generation (2G) wireless communications systems, which made the...

Smart Note Taker

The Smart NoteTaker is such a helpful product that satisfies the needs of the people in today's technologic and fast life. This product can be used in many ways. The Smart NoteTaker provides taking fast and easy notes to people who are busy one's self with something. With the help of Smart NoteTaker, people will be able to write notes on the air, while being busy with their work. The written note will be stored on the memory chip of the pen, and will be able to read in digital medium after the job has done. This will save time and facilitate life. The Smart NoteTaker is good and helpful for blinds that think and write freely. Another place, where our product can play an important role, is where two people talks on the phone. The subscribers are apart from each other while their talk, and they may want to use figures or texts to understand themselves better. It's also useful especially for instructors in presentations. The instructors may not want to present the lecture in f...