Showing posts with label OFDM. Show all posts
Showing posts with label OFDM. Show all posts

Wednesday, 22 October 2008

WiMax Vs LTE : future mobile communication trend ?


After a long debut about the next-generation cellular and WiMax deployment in the near future for the new communication module, seems they will show something to us, LTE and WiMax for future communication module. Both are still struggling to prove their capability, performance reliability and signal efficiency towards higher bandwidth requirement from community. Whihc one will win the segment? However, before we further jump into conclusion, some clarification need to be mentioned here. There are still some people really confused about those two; what are they? what they do? how great performance they can produce? how reliable they are?..Well, if we put these two together, they are almost the same. First, both are 4G technologies designed to move data rather than voice. Both are IP networks based on OFDM technology for fixed (802.16) and OFDMA (802.16m & LTE) for mobile — so rather than rivals such as GSM and CDMA, they’re more like siblings. But does the siblings all the same. no right? So, there a plenty of difference among them.

WiMax is based on a IEEE standard (802.16), and like that other popular IEEE effort, Wi-Fi, it’s an open standard that was debated by a large community of engineers before getting ratified. In fact, we’re still waiting on the 802.16m standard for faster mobile WiMax to be ratified. The level of openness means WiMax equipment is standard and therefore cheaper to buy — sometimes half the cost and sometimes even less. Depending on the spectrum alloted for WiMax deployments and how the network is configured, this can mean a WiMax network is cheaper to build. The speed for the WiMax (802.16) is up to 70 Mbps, while the mobile WiMax (802.16m) is up to 100Mbps.

Malaysia is still in progress in deploying WiMax Technology, but the condition is stillon “testing” for so long . Do not know why. Izzi is a new name in Malaysian Broadband challange and the claim to have 4G connection. Check it first before you subscribe (affraid only for the best effort - as another slumpy monopoly carrier advertise their broadband). Sprint Nextel will aslo deploy this WiMax technology to become their 4G carrier.

Whilst, The LTE, (3GPP Long Term Evolution), is the next-generation network that beyond 3G. In addition to enabling fixed to mobile migrations of Internet applications such as Voice over IP (VoIP), video streaming, music downloading, mobile TV and many others, LTE networks will also provide the capacity to support an explosion in demand for connectivity from a new generation of consumer devices tailored to those new mobile applications. Most of the Telcos believes LTE will be the standard chosen by 80 percent of the carriers in the world

LTE is the natural evolution of 3GPP GSM and WCDMA networks. It is also an evolution candidate for 3GPP2 CDMA networks. Efforts are underway to harmonize the standards. LTE itself is a new paradigm in access, with a new modulation technique, OFDM (Orthogonal Frequency Division Multiplex) or some people said it use Orthogonal Frequency Division Multiple Access (OFDMA), and antenna technology, MIMO (Multiple Input Multiple Output).

Nortel, Nokia , LG, and Alcatel-lucent are among the group who perform test on LTE deployment.

To much technical right?

The funny thing about technology businesses is that technology counts for so little in the final result. Politics, human nature, and all of the frailties inherent therein trump the technology issues in virtually every case. So, logically: LTE will win.

The cellular carriers control the market, so they control the decision. Now if the WiMAX camp could come up with something that was phenomenally better, then the cellular carrier would have to look more closely at this, but unfortunately, physics works the same for everyone. With no compelling technical advantage for WiMAX, LTE will win. Agree?

WiMax Vs LTE : future mobile communication trend ?


After a long debut about the next-generation cellular and WiMax deployment in the near future for the new communication module, seems they will show something to us, LTE and WiMax for future communication module. Both are still struggling to prove their capability, performance reliability and signal efficiency towards higher bandwidth requirement from community. Whihc one will win the segment? However, before we further jump into conclusion, some clarification need to be mentioned here. There are still some people really confused about those two; what are they? what they do? how great performance they can produce? how reliable they are?..Well, if we put these two together, they are almost the same. First, both are 4G technologies designed to move data rather than voice. Both are IP networks based on OFDM technology for fixed (802.16) and OFDMA (802.16m & LTE) for mobile — so rather than rivals such as GSM and CDMA, they’re more like siblings. But does the siblings all the same. no right? So, there a plenty of difference among them.

WiMax is based on a IEEE standard (802.16), and like that other popular IEEE effort, Wi-Fi, it’s an open standard that was debated by a large community of engineers before getting ratified. In fact, we’re still waiting on the 802.16m standard for faster mobile WiMax to be ratified. The level of openness means WiMax equipment is standard and therefore cheaper to buy — sometimes half the cost and sometimes even less. Depending on the spectrum alloted for WiMax deployments and how the network is configured, this can mean a WiMax network is cheaper to build. The speed for the WiMax (802.16) is up to 70 Mbps, while the mobile WiMax (802.16m) is up to 100Mbps.

Malaysia is still in progress in deploying WiMax Technology, but the condition is stillon “testing” for so long . Do not know why. Izzi is a new name in Malaysian Broadband challange and the claim to have 4G connection. Check it first before you subscribe (affraid only for the best effort - as another slumpy monopoly carrier advertise their broadband). Sprint Nextel will aslo deploy this WiMax technology to become their 4G carrier.

Whilst, The LTE, (3GPP Long Term Evolution), is the next-generation network that beyond 3G. In addition to enabling fixed to mobile migrations of Internet applications such as Voice over IP (VoIP), video streaming, music downloading, mobile TV and many others, LTE networks will also provide the capacity to support an explosion in demand for connectivity from a new generation of consumer devices tailored to those new mobile applications. Most of the Telcos believes LTE will be the standard chosen by 80 percent of the carriers in the world

LTE is the natural evolution of 3GPP GSM and WCDMA networks. It is also an evolution candidate for 3GPP2 CDMA networks. Efforts are underway to harmonize the standards. LTE itself is a new paradigm in access, with a new modulation technique, OFDM (Orthogonal Frequency Division Multiplex) or some people said it use Orthogonal Frequency Division Multiple Access (OFDMA), and antenna technology, MIMO (Multiple Input Multiple Output).

Nortel, Nokia , LG, and Alcatel-lucent are among the group who perform test on LTE deployment.

To much technical right?

The funny thing about technology businesses is that technology counts for so little in the final result. Politics, human nature, and all of the frailties inherent therein trump the technology issues in virtually every case. So, logically: LTE will win.

The cellular carriers control the market, so they control the decision. Now if the WiMAX camp could come up with something that was phenomenally better, then the cellular carrier would have to look more closely at this, but unfortunately, physics works the same for everyone. With no compelling technical advantage for WiMAX, LTE will win. Agree?

WiMax Vs LTE : future mobile communication trend ?


After a long debut about the next-generation cellular and WiMax deployment in the near future for the new communication module, seems they will show something to us, LTE and WiMax for future communication module. Both are still struggling to prove their capability, performance reliability and signal efficiency towards higher bandwidth requirement from community. Whihc one will win the segment? However, before we further jump into conclusion, some clarification need to be mentioned here. There are still some people really confused about those two; what are they? what they do? how great performance they can produce? how reliable they are?..Well, if we put these two together, they are almost the same. First, both are 4G technologies designed to move data rather than voice. Both are IP networks based on OFDM technology for fixed (802.16) and OFDMA (802.16m & LTE) for mobile — so rather than rivals such as GSM and CDMA, they’re more like siblings. But does the siblings all the same. no right? So, there a plenty of difference among them.

WiMax is based on a IEEE standard (802.16), and like that other popular IEEE effort, Wi-Fi, it’s an open standard that was debated by a large community of engineers before getting ratified. In fact, we’re still waiting on the 802.16m standard for faster mobile WiMax to be ratified. The level of openness means WiMax equipment is standard and therefore cheaper to buy — sometimes half the cost and sometimes even less. Depending on the spectrum alloted for WiMax deployments and how the network is configured, this can mean a WiMax network is cheaper to build. The speed for the WiMax (802.16) is up to 70 Mbps, while the mobile WiMax (802.16m) is up to 100Mbps.

Malaysia is still in progress in deploying WiMax Technology, but the condition is stillon “testing” for so long . Do not know why. Izzi is a new name in Malaysian Broadband challange and the claim to have 4G connection. Check it first before you subscribe (affraid only for the best effort - as another slumpy monopoly carrier advertise their broadband). Sprint Nextel will aslo deploy this WiMax technology to become their 4G carrier.

Whilst, The LTE, (3GPP Long Term Evolution), is the next-generation network that beyond 3G. In addition to enabling fixed to mobile migrations of Internet applications such as Voice over IP (VoIP), video streaming, music downloading, mobile TV and many others, LTE networks will also provide the capacity to support an explosion in demand for connectivity from a new generation of consumer devices tailored to those new mobile applications. Most of the Telcos believes LTE will be the standard chosen by 80 percent of the carriers in the world

LTE is the natural evolution of 3GPP GSM and WCDMA networks. It is also an evolution candidate for 3GPP2 CDMA networks. Efforts are underway to harmonize the standards. LTE itself is a new paradigm in access, with a new modulation technique, OFDM (Orthogonal Frequency Division Multiplex) or some people said it use Orthogonal Frequency Division Multiple Access (OFDMA), and antenna technology, MIMO (Multiple Input Multiple Output).

Nortel, Nokia , LG, and Alcatel-lucent are among the group who perform test on LTE deployment.

To much technical right?

The funny thing about technology businesses is that technology counts for so little in the final result. Politics, human nature, and all of the frailties inherent therein trump the technology issues in virtually every case. So, logically: LTE will win.

The cellular carriers control the market, so they control the decision. Now if the WiMAX camp could come up with something that was phenomenally better, then the cellular carrier would have to look more closely at this, but unfortunately, physics works the same for everyone. With no compelling technical advantage for WiMAX, LTE will win. Agree?

Monday, 10 September 2007

Wi-Fi as a Metro-Access Deployment Option

The Wi-Fi certification addresses interoperability across
IEEE 802.11 standards-based products. The IEEE 802.11
standard, with specific revisions, was designed to address
wireless local area coverage.

External modifications to the standard through hardware and
software allow Wi-Fi products to become a metro-access
deployment option. These two major modifications address
two different usage models:
• Fixed-access or last-mile usage—802.11 with highgain
antennas
• Portable-access or hot-zone usage—802.11
mesh networks

Wi-Fi products associated with the metro-access deployment
option use these different radio frequencies:
• The 802.11a standard uses 5 GHz in an AP-to-AP interlink.
• The 802.11b and 802.11g standards use 2.4 GHz.

The 802.11a, 802.11b and 802.11g standards use different
frequency bands; devices based on these standards do not
interfere with one another. On the other hand, devices on
different bands cannot communicate; for example, an
802.11a radio cannot talk to an 802.11b radio.
The most common deployments by WISPs for wireless metro
access to date are the 802.11b and 802.11g standards
because of interoperability and the greater range they achieve
in the 2.4-GHz band.

Each standard also differs in the type of radio-modulation
technology used, as follows:
• The 802.11b standard uses direct-sequence spread spectrum
(DSSS) and supports bandwidth speeds up to 11 Mbps.
• The 802.11a and 802.11g standards use orthogonal
frequency division multiplexing (OFDM) and support speeds
up to 54 Mbps. Because OFDM is more adaptable to
outdoor environments and interference, it is most commonly
used for metro-access solutions.

OFDM technology uses sub-carrier optimization, which assigns
small sub-carriers to users based on radio frequency conditions.
Orthogonal means that the frequencies into which the carrier
is divided are chosen such that the peak of one frequency
coincides with the nulls of the adjacent frequency. The data
stream is converted from serial to parallel, and each parallel
data stream is mapped by a modulation block. The
modulated data is fed to an inverse fast Fourier transform
(IFFT) block for processing. The IFFT block converts the
discrete modulated frequencies into a time-domain signal,
which is used to drive the radio frequency (RF) amplifier.
This enhanced spectral efficiency is a great benefit to OFDM
networks, making them well suited for high-speed data
connections in both fixed and mobile solutions.

The 802.11 standard provides for 64 subcarriers. These
individual carriers are sent from the base station (BS) or AP to
the subscriber station (SS) or client and are then reconstituted
at the client side. In non-line-of-sight (NLOS) situations, these
carriers will hit walls, buildings, trees and other objects, which
then reflect the signal, creating multi-path interference.
By the time the carrier signals reach the client for
reconstitution, the individual carrier signals are time delayed.
For example, one carrier may have been reflected once and
arrived 1 μs later than another, and a second carrier may have
been reflected twice and arrive 2 μs later. The larger number of
subcarriers over the same band results in narrower
subcarriers, which is the equivalent to larger OFDM symbol
periods. Consequently, the same percentage of guard time or
cyclic prefix (CP) will provide larger absolute values in time for
larger delays, improving resistance to multi-path interference.
Because the 802.11a and 802.11g standards use OFDM, they
are more resilient than the 802.11b standard in outdoor multipath-
prone environments. These factors were taken into
account when developing the 802.16-2004 standard. The
802.11a and 802.11g standards have one-fourth of the OFDM
symbol options for CP than in the 802.16-2004 standard.

Wi-Fi standards at a glance.

Wi-Fi Standard Frequency Modulation
802.11a 5 GHz OFDM
802.11b 2.4 GHz DSSS
802.11g 2.4 GHz OFDM

The 802.11g standard is often selected for a last-mile solution
for three reasons.
• Speed
• The ability to handle interference
• Interoperability with 802.11b-based devices

Wi-Fi as a Metro-Access Deployment Option

The Wi-Fi certification addresses interoperability across
IEEE 802.11 standards-based products. The IEEE 802.11
standard, with specific revisions, was designed to address
wireless local area coverage.

External modifications to the standard through hardware and
software allow Wi-Fi products to become a metro-access
deployment option. These two major modifications address
two different usage models:
• Fixed-access or last-mile usage—802.11 with highgain
antennas
• Portable-access or hot-zone usage—802.11
mesh networks

Wi-Fi products associated with the metro-access deployment
option use these different radio frequencies:
• The 802.11a standard uses 5 GHz in an AP-to-AP interlink.
• The 802.11b and 802.11g standards use 2.4 GHz.

The 802.11a, 802.11b and 802.11g standards use different
frequency bands; devices based on these standards do not
interfere with one another. On the other hand, devices on
different bands cannot communicate; for example, an
802.11a radio cannot talk to an 802.11b radio.
The most common deployments by WISPs for wireless metro
access to date are the 802.11b and 802.11g standards
because of interoperability and the greater range they achieve
in the 2.4-GHz band.

Each standard also differs in the type of radio-modulation
technology used, as follows:
• The 802.11b standard uses direct-sequence spread spectrum
(DSSS) and supports bandwidth speeds up to 11 Mbps.
• The 802.11a and 802.11g standards use orthogonal
frequency division multiplexing (OFDM) and support speeds
up to 54 Mbps. Because OFDM is more adaptable to
outdoor environments and interference, it is most commonly
used for metro-access solutions.

OFDM technology uses sub-carrier optimization, which assigns
small sub-carriers to users based on radio frequency conditions.
Orthogonal means that the frequencies into which the carrier
is divided are chosen such that the peak of one frequency
coincides with the nulls of the adjacent frequency. The data
stream is converted from serial to parallel, and each parallel
data stream is mapped by a modulation block. The
modulated data is fed to an inverse fast Fourier transform
(IFFT) block for processing. The IFFT block converts the
discrete modulated frequencies into a time-domain signal,
which is used to drive the radio frequency (RF) amplifier.
This enhanced spectral efficiency is a great benefit to OFDM
networks, making them well suited for high-speed data
connections in both fixed and mobile solutions.

The 802.11 standard provides for 64 subcarriers. These
individual carriers are sent from the base station (BS) or AP to
the subscriber station (SS) or client and are then reconstituted
at the client side. In non-line-of-sight (NLOS) situations, these
carriers will hit walls, buildings, trees and other objects, which
then reflect the signal, creating multi-path interference.
By the time the carrier signals reach the client for
reconstitution, the individual carrier signals are time delayed.
For example, one carrier may have been reflected once and
arrived 1 μs later than another, and a second carrier may have
been reflected twice and arrive 2 μs later. The larger number of
subcarriers over the same band results in narrower
subcarriers, which is the equivalent to larger OFDM symbol
periods. Consequently, the same percentage of guard time or
cyclic prefix (CP) will provide larger absolute values in time for
larger delays, improving resistance to multi-path interference.
Because the 802.11a and 802.11g standards use OFDM, they
are more resilient than the 802.11b standard in outdoor multipath-
prone environments. These factors were taken into
account when developing the 802.16-2004 standard. The
802.11a and 802.11g standards have one-fourth of the OFDM
symbol options for CP than in the 802.16-2004 standard.

Wi-Fi standards at a glance.

Wi-Fi Standard Frequency Modulation
802.11a 5 GHz OFDM
802.11b 2.4 GHz DSSS
802.11g 2.4 GHz OFDM

The 802.11g standard is often selected for a last-mile solution
for three reasons.
• Speed
• The ability to handle interference
• Interoperability with 802.11b-based devices

Wi-Fi as a Metro-Access Deployment Option

The Wi-Fi certification addresses interoperability across
IEEE 802.11 standards-based products. The IEEE 802.11
standard, with specific revisions, was designed to address
wireless local area coverage.

External modifications to the standard through hardware and
software allow Wi-Fi products to become a metro-access
deployment option. These two major modifications address
two different usage models:
• Fixed-access or last-mile usage—802.11 with highgain
antennas
• Portable-access or hot-zone usage—802.11
mesh networks

Wi-Fi products associated with the metro-access deployment
option use these different radio frequencies:
• The 802.11a standard uses 5 GHz in an AP-to-AP interlink.
• The 802.11b and 802.11g standards use 2.4 GHz.

The 802.11a, 802.11b and 802.11g standards use different
frequency bands; devices based on these standards do not
interfere with one another. On the other hand, devices on
different bands cannot communicate; for example, an
802.11a radio cannot talk to an 802.11b radio.
The most common deployments by WISPs for wireless metro
access to date are the 802.11b and 802.11g standards
because of interoperability and the greater range they achieve
in the 2.4-GHz band.

Each standard also differs in the type of radio-modulation
technology used, as follows:
• The 802.11b standard uses direct-sequence spread spectrum
(DSSS) and supports bandwidth speeds up to 11 Mbps.
• The 802.11a and 802.11g standards use orthogonal
frequency division multiplexing (OFDM) and support speeds
up to 54 Mbps. Because OFDM is more adaptable to
outdoor environments and interference, it is most commonly
used for metro-access solutions.

OFDM technology uses sub-carrier optimization, which assigns
small sub-carriers to users based on radio frequency conditions.
Orthogonal means that the frequencies into which the carrier
is divided are chosen such that the peak of one frequency
coincides with the nulls of the adjacent frequency. The data
stream is converted from serial to parallel, and each parallel
data stream is mapped by a modulation block. The
modulated data is fed to an inverse fast Fourier transform
(IFFT) block for processing. The IFFT block converts the
discrete modulated frequencies into a time-domain signal,
which is used to drive the radio frequency (RF) amplifier.
This enhanced spectral efficiency is a great benefit to OFDM
networks, making them well suited for high-speed data
connections in both fixed and mobile solutions.

The 802.11 standard provides for 64 subcarriers. These
individual carriers are sent from the base station (BS) or AP to
the subscriber station (SS) or client and are then reconstituted
at the client side. In non-line-of-sight (NLOS) situations, these
carriers will hit walls, buildings, trees and other objects, which
then reflect the signal, creating multi-path interference.
By the time the carrier signals reach the client for
reconstitution, the individual carrier signals are time delayed.
For example, one carrier may have been reflected once and
arrived 1 μs later than another, and a second carrier may have
been reflected twice and arrive 2 μs later. The larger number of
subcarriers over the same band results in narrower
subcarriers, which is the equivalent to larger OFDM symbol
periods. Consequently, the same percentage of guard time or
cyclic prefix (CP) will provide larger absolute values in time for
larger delays, improving resistance to multi-path interference.
Because the 802.11a and 802.11g standards use OFDM, they
are more resilient than the 802.11b standard in outdoor multipath-
prone environments. These factors were taken into
account when developing the 802.16-2004 standard. The
802.11a and 802.11g standards have one-fourth of the OFDM
symbol options for CP than in the 802.16-2004 standard.

Wi-Fi standards at a glance.

Wi-Fi Standard Frequency Modulation
802.11a 5 GHz OFDM
802.11b 2.4 GHz DSSS
802.11g 2.4 GHz OFDM

The 802.11g standard is often selected for a last-mile solution
for three reasons.
• Speed
• The ability to handle interference
• Interoperability with 802.11b-based devices