The difference between AT&T 3G and AT&T 4G
In the US, AT&T is one of the major providers for satellite TV as well as telephone and Internet service. In fact it is one of the leading providers all over the world. It uses both 3G and 4G technology in the services it provides in North America. The mobile broadband that it uses all across the US takes advantage of different technologies in GSM. Although the norm at the present time is 3G, it is expected that by the fall of 2011 AT&T will be using 4G technology. It does offer the entry level for 4G right now. This is called HSPA+. Even with 4G, this provider will still continue to provide VoLTE, which means Voice over Long Term Evolution.
The 3G network of AT&T
With about 90 million subscribers AT&T is a fully owned subsidiary company offering wireless coverage throughout the US. The technology used for the 3G network is UMTS/HSPA, which allows data to be transferred at a higher rate. They meet the standard set down by the ITU for 3G networks. For the most part, the circuit switch voice and multimedia applications are the medium for the bandwidth. This includes video share, which is a service that only AT&T offers.
In a recent study carried out on the AT&T network showed that the average downlink data rates are about 1410Kbps and for uplinks they are 773 Kbps. These are faster than that of the company’s competitors – Verizon and T mobile. The network is also reputed to be about 94% reliable and this too is much higher than that of the competitors.
AT&T is the preferred provider for Apple iPhone and the iPad. These devices have an average downlink speed of 1259Kbps and an uplink speed of 215Kbps. One important feature of the AT&T network is that by 2009, it had changed almost 90% of the 3G network to HSUPA.
The 4G network of AT&T
The next generation of mobile communication will be 4G and AT&T is currently using entry level forms of this technology. It is using both HSPA+ and LTE as the major technologies in its 4G network. At the present time AT&T is providing HSPA+ and offers a software upgrade to what is expected to be a much faster system. In fact the data transfer rates are expected to be four times higher than they are now. The only remaining hurdle is the launch of LTE (Long Term Evolution), which is expected to take place in the last quarter of 2011. The equipment for the new network will be supplied by Alcatel-Lucent and Ericsson.
The association of the LTE technology with MIMO and OFDMA will meet the standards for the speed of 4G networks as established by the ITU. The bandwidth that AT&T plans to use in the fourth generation will vary from 1.25MHz to 20MHz. All the MHz in between are multiples of 1.25KHz.
It is estimated that the downlink data rate speed will be 100Mbps and 50Mbps uplink where the data range is 50 meters. The speeds will be slowed down by AT&T to make sure that all subscribers will have efficient use of LTE. The actual speed will be from 6Mbps to 8Mbps reaching 20Mbps at peak rate.
Summary
- 3G networks currently use HSPA technology. The 4G technology that AT&T plans to use is a combination of HSPA+ and LTE.
- In 4G networks the latency is lower being below 50Mbps and in 3G networks it falls below 70Mbps.
- The average downlink and uplink data transfer rates for the 3G networks are 1410Kbps and 773 Kbps respectively. 4G promises rates between 6Mbps and 8Mbps.
- 3G networks has a bandwidth of 5MHz and in 4G it will vary between 1.25MHz and 20MHz.