A lot of schemes are proposed to exploit the transmit diversity. Distributed antenna systems (DAS) constitute one of the most attractive schemes to efficiently achieve the stringent quality of service demands of next generation wireless networks. A particular project investigates MISO assisted different transmission techniques used in DAS and the performance of downlink multi-cell DAS in terms of capacity improvement using SINR for different transmission scheme. A system level simulation tool is used to analyze the performance. Here, the aim of this research is to assess the applicability of a Repeater connected to a Distributed Antenna System (DAS) for improving indoor capacity in UMTS radio network (2100 MHz).
A guarantee of sufficient coverage and capacity for In-building areas constitutes a considerable issue in topology planning, because in both links, indoor users produce high interference to the outdoor network due to significant indoor propagation losses. Presented configuration effectively exploits effectively a Repeater system that amplifies the signal from the outdoor network and delivers it for indoor locations through distributed antenna system. Implementation of the analyzed Repeater system is straightforward as it does not require usage of separate carrier. Moreover, any separate scrambling codes do not have to be dedicated either. Conducted measurement campaigns reveal improvement of radio conditions due to Repeater implementation that results in 35% gain of down link capacity for indoor locations. Either type of headset is preferable to a phone held to the ear is the result of the jury.
The governments of Switzerland, Germany, Israel and Finland and the European Parliament all recommend using a headset or an earpiece as a precautionary measure. But expert advice differs on the type — some recommend wired, some wireless.
A wireless headset such as one incorporating bluetooth technology uses radio frequency radiation to communicate with a cell phone. This is the same form of radiation emitted by cell phones. But the signal travels only inches from the Bluetooth headset to the phone, so wireless headset emissions are lower than emissions from a cell phone, which transmits to a distant tower.
Some wireless headsets emit continuously, even when you’re not on a call. Experts recommend that if you use a wireless headset, take it off between calls.
Various research teams have found that corded headsets reduce the overall radiation exposure to the head. But some scientists report that the wire of a corded headset can act as a secondary antenna, transmitting some small amount of radiation toward the head of a user.
Whether you choose a wired or a wireless headset, any actively transmitting phone near the waist (such as in a front pocket or clipped to a belt.) will transmit radiation towards the torso and absorbed by internal organs. Ten studies now connect cell phone radiation to declines in sperm count and impacts to sperm health. But possible effects of cell phone radiation on women’s reproductive health are yet to be known; however, research on laboratory animals and studies on children whose mothers actively used cell phones during pregnancy suggest that caution is warranted.
Radiation shields such as antenna caps or keypad covers reduce the connection quality and force the phone to transmit at a higher power with higher radiation. At the moment, public health agencies in the U.S. and other countries unanimously recommend against the use of such devices since they are untested and don’t undergo government review.
Cell phones use less power and emit less radiation when they send text rather than voice signals. Texting keeps radiation away from your body.