Guide: Why LTE is Better Than GSM and CDMA

LTE, a mobile communications network protocol for high speed data and voice, will outperform GSM and CDMA. Most countries have variations of two types of networks: Global System for Mobile communications (GSM) and  Code Division Multiple Access (CDMA).

Long Term Evolution (LTE) is a fourth-generation (4G) wireless broadband technology, a standard developed in 2004 by the Third Generation Partnership Project forum (3GPP).

It is meeting their goals of high capacity, security quality of service, manageability and a consistent future-proof migration path ? unlike the present choice of GSM versus CDMA.

LTE also provides a transition from voice-centric transportation infrastructures to a fully packet switched, IP based end-to-end network model. LTE lets mobile carriers provision a new customer using software-controlled hardware rather than having to send a technician to an equipment rack to manually change dual in-line package (DIP) switch settings. In addition, LTE provides the capacity to handle:

  • multiple antenna techniques to increase overall data rate
  • better multi-path signal handling capability than CDMA technologies
  • no intra-cell interference, as the sub-carriers are for a single user in a time slot
  • enhanced interference cancellation is better for reduced inter-cell interference
  • mitigation of the cell shrinkage vs. loading phenomena of CDMA technologies
  • more efficient Multicast, Broadcast
  • lowered and more efficient control overhead
  • frequency selective scheduling for additional flexibility and efficiency

In radio, a system which uses multiple antennas at the transmitter (cell tower) and a single antenna at the receiver (handset) is named Multiple Input Single Output (MISO). MISO is what we have seen through 2007. LTE, instead, is based upon a multiple-input and multiple-output, or MIMO (commonly pronounced my-moh or me-moh), and uses multiple antennas at both the transmitter and receiver to improve communication performance. It is one of several forms of smart antenna technology. LTE network design is based upon error correction and the error corrected bit rate is shown in the below table from Motorola.

In addition to increased data rates, the latency enhancement is likely to provide a noticeable improvement in the user experience. With 3G networks, a user can expect a two-second or longer delay to set up the first connection, and then a 50-millisecond one-way latency afterwards. With LTE being all Internet Protocol (IP) and having a much flatter architecture, the initial data packet connection should be much faster – typically 50 ms, and then a five-millisecond one-way latency afterwards.

LTE can be used with many different radio frequency bands. There are planned 700MHz deployments in North America (Verizon and AT&T) and 1700MHz (MetroPCS); 900, 1800 and 2600 MHz in Europe; 1800 and 2600 MHz in Asia; and 1800MHz in Australia.

LTE chipsets, like Infineon’s Smarti LU chip seen on the right, are presently averaging over $100. 3G HSPA chipsets hit average prices around $15 to $20 in 2009, while WiMax silicon approached that level late in 2010, according to chip vendors. It is in both vendors’ and operators’ interest to reduce these costs to cut the end cost of the device and trim subsidies.

BSN* evaluated the Samsung Craft on a MetroPCS 4G network in California and we’ll be pushing out a detailed analysis shortly.