s********k
发帖数: 6180 | 1 比如国内有800M和1900M，800M按照官方观点是非常适合发展农村市场.这个原因是什么
？难道因为可能的传播的距离远？比较适合农村地广人稀（相对）的情况。那么1900M
的优势又在哪里？主频不同在实际应用中最主要的差别是什么？ |
g*****e
发帖数: 87 | 2 800M is mainly for coverage and 1900M is mainly for capacity due to their
different propagation characteristics.
From system and handsets side, no difference. UMTS and GSM chipsets are
capable of handing different bands at the same time. |
g******s
发帖数: 410 | 3 Why is 1900MHz mainly for capacity? To me, it is only because the spectrum f
rom 800MHz - 900MHz is too crowded. Can you explain more? Thanks.
【在 g*****e 的大作中提到】
: 800M is mainly for coverage and 1900M is mainly for capacity due to their
: different propagation characteristics.
: From system and handsets side, no difference. UMTS and GSM chipsets are
: capable of handing different bands at the same time.
|
z*****n
发帖数: 7639 | 4 you are right.
the bandwidth allocated to GSM at 900M is only 25MHz.
at 1800M it is 75MHz.
However, it is true that a lower carrier frequency
can make wider coverage.
f
【在 g******s 的大作中提到】
: Why is 1900MHz mainly for capacity? To me, it is only because the spectrum f
: rom 800MHz - 900MHz is too crowded. Can you explain more? Thanks.
|
r******s
发帖数: 8 | 5 880~915MHz
1710~1785MHz
【在 z*****n 的大作中提到】
: you are right.
: the bandwidth allocated to GSM at 900M is only 25MHz.
: at 1800M it is 75MHz.
: However, it is true that a lower carrier frequency
: can make wider coverage.
:
: f
|
z*****n
发帖数: 7639 | 6 oh, 10M more were added later...:)
but not in all the countries.
【在 r******s 的大作中提到】
: 880~915MHz
: 1710~1785MHz
|
s********k
发帖数: 6180 | 7 好像这个就是为什么中国联通的GSM表现不如中国移动的原因之一，联通用的是800M频
段但是移动用的是1900M频段。联通虽然吃亏但是由于还有CDMA频段，也不好说什么，
结果导致联通两个网络先天不足，后天经营维护也不行。所以差距才拉大的
【在 z*****n 的大作中提到】
: you are right.
: the bandwidth allocated to GSM at 900M is only 25MHz.
: at 1800M it is 75MHz.
: However, it is true that a lower carrier frequency
: can make wider coverage.
:
: f
|
g*****e
发帖数: 87 | 8 Frequency allocation is almost different from country to country.
China mobile has both 900M and 1800M GSM sites.
Operator can do tighter frequency reuse pattern on 1800M/1900M and build
more sites to handle urban high density traffic area. Of course the
frequency penetration is weak on 1800M and 1900M and in door coverage is
poor.
700M/800M/900M are used to fill in the coverage holes and sometimes for
indoor coverage. |
z*****n
发帖数: 7639 | 9 china unicom's problem is caused by two reasons:
1. operating totally two different systems makes
the cost of operation much higher.
2. for both systems, the bandwidth allocation is
relatively small. Thus the trunk efficiency is
much lower than China Mobilcom and less profitable.
【在 s********k 的大作中提到】
: 好像这个就是为什么中国联通的GSM表现不如中国移动的原因之一，联通用的是800M频
: 段但是移动用的是1900M频段。联通虽然吃亏但是由于还有CDMA频段，也不好说什么，
: 结果导致联通两个网络先天不足，后天经营维护也不行。所以差距才拉大的
|
z*****n
发帖数: 7639 | 10
not true, actually frequency allocation for GSM is
more or less the same in most countries, except north America.
800-900MHz signal covers wider area is due to the diffraction
feature of this frequency band is better than that around 2GHz.
Actually the penetration ability of 2Ghz signal is better than 900Mhz
【在 g*****e 的大作中提到】
: Frequency allocation is almost different from country to country.
: China mobile has both 900M and 1800M GSM sites.
: Operator can do tighter frequency reuse pattern on 1800M/1900M and build
: more sites to handle urban high density traffic area. Of course the
: frequency penetration is weak on 1800M and 1900M and in door coverage is
: poor.
: 700M/800M/900M are used to fill in the coverage holes and sometimes for
: indoor coverage.
|
