Conclusion

Overall, LTE capabilities include:

• Downlink peak data rates up to 326 Mbps with 20 MHz bandwidth
• Uplink peak data rates up to 86.4 Mbps with 20 MHz bandwidth
• Operation in both TDD and FDD modes
• Scalable bandwidth up to 20 MHz, covering 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, and 20 MHz in the study phase
• Increased spectral efficiency over Release 6 HSPA by two to four times
• Reduced latency, up to 10 milliseconds (ms) round-trip times between user equipment and the base station, and to less than 100 ms transition times from inactive to active

Although LTE is still under the trial stage where we still need to wait for some time before it is officially rolled out in Malaysia, many investors seems very confident with this technology and have foreseen its good prospect on the market in the near future.

OFDM

Orthogonal Frequency Division Multiplexing (OFDM) is the method of modulation that uses in both LTE and WiMAX. So, what is exactly OFDM and what are the advantages of using it?

OFDM is a multicarrier modulation scheme utilized as a digital multicarrier modulation method. This technology is used in multiple communications. For instance, in wired communications; DSL, power line communications (PLC) and in wireless communications; wireless LAN (WLAN), terrestrial digital system digital video broadcasting terrestrial (DVB-T) or digital video broadcasting-handheld (DVB-H) amongst others. Its working principle is such that dividing a high rate data stream into several parallel smaller data streams or we call it "channel", and modulate each of the streams on separate carriers, called subcarriers.

In order to keep each OFDM symbol independent among others over the channel, it is necessary to introduce a guard time between each symbol. A larger guard band is able to guarantee a low possibility of interference between OFDM symbols (ISI).

Also, the other advantages of OFDM including:

Reduce computational complexity. Fast Fourier Transform (FFT) and Inverse Fourier Transform (IFFT) can be used to implement the OFDM.

Delay the degradation of performance under the delay spread. As the delay spread grows over the maximum delay spread which was designed for optimal performance, performance of an OFDM degrades slowly.

Exploitation of frequency diversity. OFDM facilitates coding and interleaving subcarriers in the frequency domain, which provide robustness against burst errors, parts of the data that are transmitted into spectral bad channel conditions.

Can be used as a multi access scheme. The resources are partitioned among other users. However, this is normally used in Mobile WiMAX.

The Differences Between LTE and WiMAX

At the moment, the biggest rival to LTE technology is WiMAX. They offer almost identical benefits in terms of speed and coverage they are completely different technologies. Worldwide Interoperability for Microwave Access (WiMAX) is the industry term for a long-range wireless networking standard. Both LTE and WiMAX technology has the potential to deliver high-speed mobile broadband Internet access. They appear to have the similar goals for enabling worldwide wireless data network connectivity for cell phone, laptops and other computing devices. This causes many are confused as to what the difference is between them because these are two systems developing along the same lines but optimized to work somewhat differently. In this post, the difference between LTE and WiMAX from different aspects will be highlightened.

The primary difference between LTE and WiMAX are the differences in upbringing, meaning both of them having the similar frameworks of technology but ties between 2 standards. The other differences included are:

Background:

LTE is the most recent in the line of the GSM broadband network evolvement. The ever-improved technologies under 3GPP family from GSM, GPRS, EDGE, WCDMA to HSPA and finally to LTE emerged and become the fastest form of internet connection. LTE offers data speeds of up to 300Mbps for downlink and 75Mbps in uplink.

WiMAX, another 4G technology evolved from a Wi-Fi, IP-based background. It uses the IEEE 802.16 standard established by IEEE standards board in 1999 for the global deployment of wireless broadband networks. The standard was then amended into many versions and finally the most popularly used standard for WiMAX - 802.16e turn up. The standard is then further revised and continued to amend and each amended version of WiMAX standard increases coverage capacity and service performance. After that, WiMAX have taken over by WiMAX Forum.

Backwards Compatibility:

LTE is designed to be backwards compatible with GSM and HSPA. This is to ensure the connectivity of the mobile device when it exceed the coverage of LTE network, it can fall back on a 2.5G or 3G network, assuming it has the requisite radio technologies.

WiMAX, the updated version called "Mobile WiMAX" is backwards compatible with the previous WiMAX standard 802.16d, known as "Fixed WiMAX".

Speed:

LTE offers a speed of 300Mbps for downlink and uplink speeds of 75Mbps at peak rates.

“Fixed WiMAX” can offer speeds of up to 75Mbps and “Mobile WiMAX” offer speeds of up to 30Mbps. However, the standard 802.16m enable the service offer speeds of up to 1Gbps.

IP:

Both LTE and WiMAX are IP based instead of mobile phone network-based.

LTE follows the earlier telephony GSM technology while WiMAX breaks from the IP pattern of its Wi-Fi predecessor.

All voice applications for both WiMAX and LTE are managed via VoIP.

OFDM:

Technically, while both have a scalable OFDM downlink, LTE is far more flexible, allowing many more combinations of tones, at the expense of complexity (DFT instead of the 2^n of WiMAX which allows FFT).

WiMAX has an OFDM uplink, while LTE adds another step to generate a single carrier modulation (SC-FDMA), which is more power efficient in the terminal, saving battery power (at the expense of slightly more complexity in terminal, and significantly more in base station)

FDD and TDD:

LTE primarily allows both FDD and TDD for full duplex on two 5MHz channels.

WiMAX uses TDD for half duplex on one 10MHz channel.

SIM and Customer ID Systems:

LTE will require the use of a SIM in order to operate. This will be convenient for cellular devices that are already compatible with a SIM, but not for laptops and other technological devices without SIM interfaces.

WiMAX however, does not require a SIM or any other hardware token. Therefore, all authentication methods used to identify a customer’s device will be easily entered into several devices. The one WiMAX device can be configured to use one set of customer ID settings, enabling it to be easily used for multiple WiMAX networks in different locations, or within the same network but for different customer identities. This is an example of the major difference between WiMAX and LTE.

WiMAX is more of an open Internet service and its devices will be compatible with most all Internet devices. LTE, on the other hand, is more exclusive to certain ISPs.

Application:

WiMAX is primarily aimed at Greenfield (new) fixed to mobile deployments while LTE is mostly aimed at incumbent (existing) deployments that must work with existing networks and business practices

Wireless Spectrum:

WiMAX has not defined any one fixed band for its wireless signaling. Outside the U.S., WiMAX products have conventionally targeted 3.5GHz as that is an emerging standard for mobile broadband technologies generally. In the U.S., however, the 3.5GHz band is mostly reserved for use by the government. WiMAX products in the U.S. have typically utilized 2.5GHz instead although various other ranges are also available. LTE providers in the U.S. intend to use a few different bands including 700MHz (0.7GHz).

Cost:

The cost of the two technologies will also differ, and this may have a major impact on which of the technologies network providers opt for. In general, LTE has a lower cost compared to WiMAX

Overall, LTE is faster, but WiMAX has more ubiquity. Additionally, WiMAX is already commercially available and many ISPs worldwide are getting the feel of it, while LTE is still under construction. This may offer LTE an opportunity to become a more sophisticated network and to provide proficiency in areas where WiMAX is lacking. However, neither technology is surmised to replace Wi-Fi home networks and hotspots. For consumers, then, the choice between LTE and WiMAX comes down to which services are available in their region and offer better speed and reliability.

Rohde & Schwarz LTE Basics Webinar - Part 01

3G vs. 4G Wireless - What is the Difference?

Differences of LTE Technology to GSM and UMTS

The key difference of 4G to 2G and 3G is the new underlying radio access technology. LTE uses Orthogonal Frequency Division Multiple Access (OFDM) for downlink which enables a high peak data rates achieved in high spectrum bandwidth. On the other hand, Multiple Input Multiple Output (MIMO) systems form an essential part of LTE makes the ambitious requirements for throughput and spectral efficiency viable. MIMO refers to the use of multiple antennas at transmitter and receiver side. Although the use of Wideband Code Division Multiple Access (WCDMA) radio technology on 2G and 3G has efficiency as good as OFDM in delivering peak data rates of about 10 Mbps in 5 MHz of bandwidth. Achieving peak rates in the 100 Mbps range with wider radio channels, however, would result in highly complex terminals and is not practical with current technology. This is where OFDM provides a practical implementation advantage.

A pure OFDMA approach on the uplink results in high Peak to Average Ratio (PAR) of the signal, which compromises power efficiency and, ultimately, battery life. Hence, LTE uses another mean for the uplink transmission, called Single Carrier FDMA (SC-FDMA), SC-FDMA is somewhat similar to OFDMA, but has a 2 to 6 dB PAR advantage over the OFDMA method used by other technologies such as WiMAX.

Another distinctive difference is the characteristic of EUTRA (Evolved UMTS Terrestrial Radio Access Network or Evolved Universal Terrestrial Radio Access Network). EUTRA is unrelated and incompatible with WCDMA. It is categorized as a completely new air interface from the ancestor technologies. All the traffic and signaling is sent over shared channels for both directions of transmission-downlink and uplink because of the total lack of dedicated channels.

The OFDMA approach is also highly flexible in channelization, and LTE will operate in various radio channel sizes ranging from 1.4 to 20 MHz. LTE also boosts spectral efficiency.

Moreover, LTE only support the hard handover. Considering then that handover creates an interruption time in the user plane, the handover performance in terms of success rate and delay of execution is utmost importance.

An important aspect of the design mentioned in Release 8 (Rel-8) LTE is the ability of LTE to use spectrum in a flexible fashion. This allows, for example, an initial LTE deployment with a small amount of spectrum as well as migration of GSM/CDMA frequency bands. Then as the usage of LTE grows, the system can efficiently migrate to increasingly larger bandwidths.

The overall objective for LTE is to provide an extremely high performance radio-access technology that offers higher data rates and truly mobile broadband with full vehicular speed mobility provided and that can readily coexist with HSPA and earlier networks. Because of scalable bandwidth, operators will be able to easily migrate their networks and users from HSPA to LTE over time.

LTE assumes a full Internet Protocol (IP) network architecture and is designed to support voice in the packet domain. It incorporates top-of-the-line radio techniques to achieve performance levels beyond what will be practical with CDMA approaches, particularly in larger channel bandwidths. However, in the same way that 3G coexists with second generation (2G) systems in integrated networks, LTE systems will coexist with 3G and 2G systems. Multimode devices will function across LTE/3G or even LTE/3G/2G, depending on market circumstances.

3GPP Long Term Evolution (LTE) Technology Overview by Steepest Ascent

What is LTE - This Tutorial Explains LTE

An introduction to LTE Technology

Long Term Evolution, abbreviated as LTE, marketed as 4G LTE, is currently the fastest, most advanced network service. It belongs to 3rd Generation Partnership Project (3GPP) work item, which is an international collaboration of a number of telecommunications standard who standard produce standards for UMTS (3rd Generation Mobile System, 3G GSM).

LTE is part of the GSM evolutionary path for mobile broadband, following EDGE, UMTS, HSPA and HSPA+ (HSPA Evolution). It is a promising technology offer users a significantly higer data rates, higher system throughput, and lower latency delay critical services compared to 3GPP ancestor UMTS.

LTE is design to has architecture centered on Internet Protocol (IP), an excellent support for browsing Websites, VoIP and other IP-based services are provided. LTE can theoretically support downlink peak rates at 300Mbps and uplink peak rates of 75Mbps (based on experiment trials). In practice the actual bandwidth available to an individual LTE subscriber will likely to be significantly less.

LTE is not just the next generation of wireless technology, LTE is an ongoing living standards. LTE is a standard that will continuously improve over time. Most leading operators, device and infrastructure manufacturers, as well as content providers expect LTE to be the standard of cellular networks for at least the next decade, possibly even beyond!