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O conteúdo do BLOCO tem forte vinculação com os debates nos Grupos de Discussão Celld-group e WirelessBR. Participe!
19/03/10
• "Março com 4G" (25) - XGP (eXtended Global Plataform)
Olá, ComUnidade WirelessBRASIL!
01.
Prosseguimos com o tradicional evento virtual "Março com 4G", uma
parceria informal entre a ComUnidade e o Portal
e-Thesis.
O evento é um "esforço concentrado" que dura 31 dias e prossegue o ano todo com
os boletins semanais "4G Etc" do e-Thesis.
02.
Ontem, quinta-feira, tivemos mais um boletim semanal "4G Etc" do e-Thesis.
Já são três neste mês de março, dentro do "evento":
• "Março
com 4G" (24) - Terceira semana: Boletim "4G Etc" do e-Thesis
• "Março
com 4G" (17) - Segunda Semana: Boletim "4G Etc" do e-Thesis
• "Março
com 4G" (16) - Primeira semana: Boletim "4G Etc" do e-Thesis
03.
No boletim da semana passada, todos notaram, claro, uma referência à uma
tecnologia não muito citada ou conhecida: XGP (eXtended Global
Plataform): :-)
A matéria foi esta, transcrita mais abaixo:
Fonte: e-Thesis
[11/03/10]
O caminho para a 4G não é uma via de mão-única - por In-Stat
Recorte:
"A indústria de celulares tem sido um campo de batalha
entre os diferentes padrões de tecnologia de comunicação impulsionados pela
indústria e a política regional. O caso da Super 3G/4G não parece ser diferente.
Mesmo assim, a indústria está em vias de se concentrar em apenas três padrões -
LTE, WiMAX e XGP. Apesar das diferenças entre as tecnologias, os três
padrões são baseados na tecnologia OFDM e representam a transição para redes de
comunicação baseadas em IP. Ao contrário das gerações anteriores, porém, essas
semelhanças tornam-se mais fáceis para os vendors de silicone suportar mais de
uma tecnologia em um único chip." (...)
04.
No Boletim de ontem encontramos mais uma referência à XGP ( e também à
5G!!!) nesta excelente matéria:
Fonte: e-Thesis
[18/03/10]
Smart grid apressa a chegada da 4G no Brasil - por Jana de Paula
(não transcrita nesta mensagem)
(...) E demos esta volta quase completa para chegarmos às
tecnologias de comunicação móvel - LTE, WiMAX e XGP, este último um
padrão japonês mais disseminado na Ásia, ao menos por enquanto. O fato relevante
nesta questão das tecnologias 4G é que elas são bem parecidas e todas já prevêem
a Internet das Coisas e o conceito de objeto a objeto. (...)
05.
Mais abaixo estão duas transcrições como resultado de uma visita ao website
do XGP Forum:
- What is
XGP technology?
-
Features and Outlines
Recomendo a visita ao website para ler no original pois pode ter ocorrido
deformação de tabelas no copiar/colar.
Comentários?
Boa leitura!
Um abraço cordial
Helio
Rosa
----------------------------------------------
Fonte: e-Thesis
[11/03/10]
O caminho para a 4G não é uma via de mão-única - por In-Stat
A indústria de celulares tem sido um campo de batalha entre os diferentes
padrões de tecnologia de comunicação impulsionados pela indústria e a política
regional. O caso da Super 3G/4G não parece ser diferente. Mesmo assim, a
indústria está em vias de se concentrar em apenas três padrões - LTE, WiMAX e
XGP. Apesar das diferenças entre as tecnologias, os três padrões são baseados na
tecnologia OFDM e representam a transição para redes de comunicação baseadas em
IP. Ao contrário das gerações anteriores, porém, essas semelhanças tornam-se
mais fáceis para os vendors de silicone suportar mais de uma tecnologia em um
único chip.
De acordo com análise da In-Stat, no relatório "New Baseband Solutions fuel
Mobile Broadband Devices", os sistemas do tipo Software Defined Radios (SDRs)
têm sido uma realidade em silício por várias gerações, devido à necessidade de
apoiar as bandas de frequências múltiplas e/ou normas 2G/3G. Com as soluções de
próxima geração, no entanto, usando tecnologias semelhantes, é mais fácil
trabalhar através de uma arquitetura programável num modem combinado com IP
dedicado ou configurável para lidar com a interface de rede e a segurança.
O resultado disto é que muitos fornecedores de chipsets de banda já consideram a
adoção de várias tecnologias de apoio através de uma arquitetura SDR. Até agora,
os novos operadores de mercado que viram a transição para tecnologias 4G como
uma oportunidade de ruptura, parecem tomar a liderança. Empresas como Comsys,
que anunciou recentemente chipset em banda WiMAX + GSM, e a Wavesat, que é a
primeira empresa a apoiar todos os três padrões de próxima geração, LTE, WiMAX e
XGP, num único chip surgem como os principais inovadores. Mesmo a Intel, que já
oferece os chipsets WiMAX e tem uma licença em 3G, através de uma parceria com a
Nokia, tem sugerido a possibilidade de apoiar a LTE no futuro. E, temos a
certeza de ver 3G + soluções LTE da indústria líder através da Qualcomm, mesmo
que o apoio ao WiMAX esteja fora de questão.
Assim, mal o mercado de banda base passou a ser considerado mais uma commodity,
com pouca diferenciação, a 4G e a Lei de Moore, mais uma vez, transformaram a
tecnologia numa corrida competitiva
---------------------------
FAQ
What is
XGP technology?
Q1. What is XGP technology?
A.
XGP is a TDD-based broadband wireless telecommunication systems standardized in
September 2007.
* XGP is one of the Broadband Wireless Access（BWA） technologies recommended in
ITU-R Advice M. 1801.
* XGP adopts OFDMA/TDMA/TDD as access method.
* XGP grants improved frequency efficiency per unit by adopting ADC, AAA, SDMA
and MIMO technologies.
* The distinguished technology known as Autonomous Distributed Control (ADC)
achieves the method of free scalable cell planing from macro to micro without
interference.
* As one area is always constructed with a certain amount of micro cells, it is
hard for all users to concentrate on one cell station. Therefore, per user
throughput doesn’t deteriorate easily even when the total amount of users
increases in that area.
* Precise cell design is no longer needed owning to Autonomous Distributed
Control (ADC). Therefore, it becomes easy to build extra cells in time of need.
Q2. What kind of organization is XGP Forum?
A.
XGP Forum is a non-profitable organization established in April 2009 to diffuse
the standardization of XGP technology and to promote the establishment of XGP
facilities worldwide.
The organization is financed and operated by members, including
telecommunication institutions, operators and vendors. Four Working Groups under
the forum carry out respective activities to meet one same target to make XGP a
future trend on the world wireless market.
Q3.
What are the obligations and advantages to accede to the forum?
A.
On applying for XGP Forum membership, a candidate is requested to sign to agree
to the basic policies of XGP Forum. A member also bears the obligation to follow
the forum’s IPR policy.
A member can collect and exchange the market information with other members at
the General Meeting held once a year. A member can participate in activies of
Working Groups to influence the determination of marketing direction as well as
the amendment of XGP documents. A member enjoys the priviliege to access
information at earlier time too.
Q4. Why shall XGP be the future trend?
A.
Prevailing mobile systems based on macro cells face ultimate problem of maintain
per-user data transmission speed and capacity, while XGP, which can prodive
scalable cell system can easily solve this pitfall by flexible increase of cells.
Prevailing mobile systems based on FDD technology, while XGP is based on TDD,
which provides opportunities for prospective operators to utilize TDD band
worldwide.
Prevailing BWA technologies like WiMax face challenge on high-speed movement,
while XGP, with over ten years’ experience of operation and development, has
learned various ways to solve handover problem.
Q5. What frequencies will XGP technology be operated on?
A.
XGP is expected to be operated on 1GHz to 3GHz frequency band. The system
bandwidth can be selected from 2.5MHz, 5MHz, 10MHz or 20MHz.
---------------------------------
OFDMA/TDMA/TDD
XGP adopts OFDMA/TDMA as multi dimension access method and TDD as duplex method.
Besides FDMA/TDD method, SC-FDMA/TDD method can also be adopted for UL (uplink)
.
The co-existence of OFDMA/TDD and SC-FDMA/TDD method is possible during uplink.
The structure of TDMA slot is symmetrical with 625 us x 4 slots for uplink and
625 us x 4 slots for downlink. This structure is the same with the existing PHS
system, which made its co-existence with XGP possible.
The symmetrical structure of TDMA slot guarantees its good affinity with AAS and
SDMA. XGP adopted AAS and SDMA technology to improve the efficiency in using
radio frequency resource.
The technical reference for XGP are displayed in the following charts: General
parameter for XGP
Duplex method - TDD
Downlink access method - OFDMA/TDMA
Uplink access method - OFDMA, SC-FDMA/TDMA
TDMA slot period - 625 us
TDMA frame period - 5 ms
Number of slots in one frame 8 slots, 4 slots for transmission and 4 slots for
reception symmetrically (formato da tabela distorcido na
cópia: consulte a fonte!)
System bandwidth [MHz]
1.25 2,5 5
10
20
Effective channel bandwidth [MHz] 0.9 1.8
3.6 8.1 9
16.2 17.1 18
Guard bandwidth [MHz]
0.35 0.7 1.4 1.9
1 3.8 2.9
2
Number of subchannels
1 2 4
9 10 18
19 20
Total number of PRU
4 8
16 36 40
72 76 80
Individual parameters for each system bandwidth
The following chart displays TDMA/TDD method adopted in existing PHS system and
OFDMA/TDMA/TDD method adopted in XGP.
One communication channel is assigned to one timeslot in existing PHS.
Taking advantage of the OFDM feature of XGP, multiplexing plural units (PRU) in
one timeslot is realized.
The amount of multipliable PRUs can increase or decrease according to the system
bandwidth.
Dynamic Channel Assignment by DCA
The PRU to be used in XGP adopts DCA method to execute “carrier sensing”
function to detect if a source has already been used
by other users, hence, to avoid interference with other users while assigning
adaptive channel. That is, BS carries out carrier sensing after receiving
a wireless link establishment demand from BS. Unused resource of PRU is assigned
to the demanding user according to the result of carrier sensing.
By adopting DCA method, the centralized control device in wireless base station
is saved and Autonomous Decentralized Control is realized.
As one base station can share PRU with its adjacent base stations, installation
design on adding new base stations becomes unnecessary
Micro Cell
Mobile system such as GSM and W-CDMA adopts macro cells with each covering an
area of several kilometer to several ten kilometers in radius.
On the other hand, XGP adopts micro cells with each covering an area of no more
than several hundred meters in radius.
The reasons to choose micro cell system are stated below:
1, Per unit efficient on frequency usage improves and system capacity increases.
This is how flat rate service becomes possible .
2, As service at reasonably affordable rate begins, more cell stations shall be
installed to cover more areas and more users.
3, Autonomous Distributed Control function is activated in heavy traffic areas
with plural cell stations. Hence, per user throughput is maximized.
4, Comparing the declining rate of throughput by number of increased users in
certain area, micro cell system suffers a lower one than macro cell system,
which covers the whole area with one cell.
Since reduction of electric output to the terminal is realized, size of the
terminal can be minimized and battery becomes more durable.
Meanwhile, base station can be minimized for the same reason.
2, Hence, cell station can be installed in narrow and closed space like inner
building or underground street.
3, Layout of cell stations can be carried out in accord with traffic condition,
such as increasing cell density in area with concentrated access.
4, Besides, when on cell station suffers unexpected breakdown, other cell
stations around the area can take instant action as complement.
5, Therefore, we consider micro cell system a better communication system at
time of disaster.
Two MAC Methods
The Mac methods adopted by PHS are QS-Mode and FM-Mode.
QS-Mode is a fixed assignment method that assigns PRUs as CSCH to all users. As
wireless band is occupied by specified user during the assignment, the mode is
adaptive to services such as voice communication with high demand of real time
and high possibility to capture random data.
FM-Mode is a fixed assignment method that assigns one PRU as ANCH to all users.
PRU for communication (EXCH) is dynamically
assigned from each TDMA frame by MAP in the ANCH. That is, EXCH is shared by
plural users instead of being monopolized by one user.
FM-Mode is adaptive to services such as high speed data communication as it can
respond to the burst increase and decrease of data instantly.
QS-Mode is always applied to control users who occupy the bandwidth in voice
communication and FM-Mode is always applied to control users in data
communication.
QS-Mode can also be used to control low-speed packet communication together with
voice communication, in case when bandwidth for a system Is narrow.
Besides, QCS-ID, which is adopted in XGP, can realize the function to assign
multiple services to one user.
Overcoming the Weak Points of Micro Cell System
XGP takes into consideration of the adoption of macro cells as supplyment to
micro cells during system deployment.
By doing this, times for handover reduce as macro cells are adopted to cover
area that correspond to connect requests during high speed movement. Therefore,
communciation quality is expected to improve during handover.
In addition, it is neccessary to adopt plural base stations to cover a big area
with wireless network that's constructed of micro cell only. Hence, it is most
practical to expand service area by building micro cell system in areas with
dense polution and adopting macro cell system in areas with sparse population.
Terminal Valuation and Development Cost
As long as a terminal keeps one PRU for transmitting and receiving data, it can
be used for communication in XGP system.
That is, the system doesn’t request all terminals to hold ability to
transmitting and receiving data with full bandwidth.
One can choose OFDMA or SC-FDMA as UL access method according to the function of
a terminal.
If SC-FDMA is chosen as the UL access method, the development of terminal can be
easier as the disposal process can be better simplified than OFDMA.
For example, high-end terminal for high-speed communication uses OFDMA for both
UL and DL communication and is equipped with wireless device that can transmit
and receive data with full bandwidth.
Low-end terminal used basically for voice communication uses SC-FDMA for UL
communication and is equipped with only one PRU to transmit and receive data, in
order to reduce cost.
This feature allows development of terminals with different functions and usages
by choosing access method for UL and bandwidth for data transmission.
That is, developing different types of terminals in correspondence with
different users’ needs becomes possible.
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