Daily Archives April 6, 2019

Distributed Antenna Systems For Indoor Cellular Network

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Some 70 – 80% of mobile traffic originates from inside buildings. This is especially true in urban environments where the focus of the mobile user is on high data rates. For mobile 3G network, only serving macro base station within a few hundred meters of the building can provide sufficient level of RF signal to support indoor voice/data services. In realty, only a few buildings will fall into this category. Soft handover in 3G network will further increase the traffic load on the network since each indoor mobile phone can be serviced by more than one macro cells (base stations). In order to provide indoor high speed mobile data services such as HSPA (High speed Packet Access) or EVDO (Evolution – Data Optimized) services, the only solution is an indoor Distributed Antenna Systems (DAS).Get additional information aboutĀ Distributed Antenna System Design Tampa, FL

DAS is used to distribute the RF signal evenly with sufficient strength inside a building to provide 3G voice and data services. DAS can be used to isolate the indoor network from the outdoor serving macro cells to eliminate the soft handover of the indoor mobile phone. This will reduce the traffic load and increase the speed of the 3G network. For HSPA high speed data service, indoor DAS can also provide isolation between serving and non-serving cells of the outdoor network. This means less co-channel interference in the HSPA serving cell and results in higher data rate for the HSPA service. To dominate the building with indoor coverage, directional antennas can be deployed at the edge and corners of the building and pointing towards the center of the building. The total indoor area is dominated by the indoor cell and at the same time minimizes leakage to the macro network.

DAS distributes a uniform dominant RF signal inside the building by splitting the signal from the indoor base station to multiple indoor antennas to provide coverage throughout the building. DAS can be classified as passive or active. Passive DAS uses passive components to distribute the RF signal. These passive components are coax cable, splitters, terminators, attenuators, circulators, couplers and filters (duplexer, diplexer or triplexer). Planning DAS includes calculating the maximum loss from base station to each antenna in the systems and does the link budget for the particular area that each antenna covers. The passive DAS design needs to adapt to the limitation of the building regarding the restriction to where and how the heavy coax cable can be installed. A detail site survey of the building needed to be done to make sure that there are cable routes to all antennas.

Active DAS has the ability to automatically compensate for the losses of the cables interconnecting the components in the system by using internal calibrating signals and amplifiers. It does not matter what the distance between the antenna and the base station, all antennas in an active DAS will have the same performance (same noise figure and downlink power). Active DAS consists of a master unit (MU) connected to multiple expansion units (EU) with optical fiber up to 6 km in length. Each EU in turns connects to multiple remote units (RU) with thin coax or CAT5 cable up to 400m in length. The MU controls and monitors the performance of the DAS. The EUs are distributed throughout the building and the RUs are installed close to the antenna. A wideband active DAS can support multiple radio services, GSM, PCS, UMTS, EVDO, WiMax and Wi-Fi.

Due to the loss and attenuation in the coax cable and passive components, passive DAS is only used in smaller building covers by a small number of indoor antennas to keep its degrading impact on HSPA performance to a minimum. For larger building, active DAS is used because it does not have cable and component loss and can boost the HSPA performance to the maximum. Troubleshoot in passive DAS is difficult and any fault in the systems will not raise an alarm at the base station because there is no surveillance of errors in the system. Active DAS monitors all units in the system and in the event of malfunction; it will send an alarm to the base station which enables the operator to pinpoint the source of the problem. Hence, active DAS is the preferred solution for large building with a lot of indoor antennas.

About Dog Strollers

A few months ago my dog injured one of his legs in an accident. I found myself carrying him everywhere after that. At the risk of sounding insensitive, I found this to be a little annoying after awhile. I found myself racking my brain on different ways to transport my dog around when it finally hit me: a dog stroller. This prompted me to do some research on this up and coming mode of pet transportation, and I found some very interesting qualities to subscribing to this lifestyle.

Primarily, buying a pet stroller for my injured pooch was really the most comfortable way to get him from A to B, for both him and myself. I was carrying him in my arms and walking all around the city, where my arms would get heavy and start to ache. It was also difficult to find a comfortable position for the guy where his injured leg would not bother him. So that was reason enough to convince me that a plush, comfortable dog stroller would solve all of our problems.Have a peek at this siteĀ when you can’t carry your dog.

After deciding to make this leap and performing further due diligence, I found out that dog strollers are extremely affordable, reinforcing my decision. I kept thinking how lucky I was that there was not only a solution to subdue my dog’s pain and suffering, but it was not even a financial burden on me! I also found that there is no shortage of online retailers specializing in the sale of pet strollers. I was able to hop online, Google the term “dog stroller”, and just like that I was able to compare and contrast the wonderful world of dog strolling.

To recap, it is important to understand that if you have a pet that is having trouble getting around then a dog stroller is probably a no-brainer purchase. They are affordable, comfortable, and will make life easier for both you and your pet.