How can Frequency Hopping increase capacity of a Network ?

[Junaid Alam]

How can Frequency Hopping increase capacity of a Network ?

 

[Junaid Alam]

Re: How can Frequency Hopping increase capacity of a Networ

This question is in regard to GSM

 

[flatulent]

Re: How can Frequency Hopping increase capacity of a Networ

Any of these spreading methods halves the capacity of a network compared to an intelligent assignment of frequency and time slots.

These methods are used on the unlicensed bands because the units cannot coordinate with each other for an orderly sharing of resources.

 

[kima]

Re: How can Frequency Hopping increase capacity of a Networ

The main purpose of frequency hopping is to improve transmission quality on the air interface. The effects of fading due to multipath reflections can be reduced since the fading pattern is frequency dependent. In addition, the resistance against co-channel interference increases.

With frequency hopping the speech quality perceived by the end user will be significantly better and the number of dropped calls will decrease.

The system planning margin can be reduced. This contributes to a network with higher capacity and/or higher speech quality.


Regards,

kima

 

[Katerina]

If one frequency suffers from constructive or destructive inerference is changed through the proccess of hopping with other "good" frequencies so that the user can have an average high quality received signal. If this "bad" frequency was standing alone, a lot of calls would be dropped. So the problem is "shared" and "mixed" with good feq and as a result this increases the networks capacity.

 

[DonJ]

Re: How can Frequency Hopping increase capacity of a Networ

One additional feature is to reduce the access collisions. For certain ISM bands, you must apply either FHSS or DSSS in your system.

All the best

 

[timber23]

Re: How can Frequency Hopping increase capacity of a Networ

How can Frequency Hopping increase capacity of a Network ?

I suppose Junaid's question is trying to ask why more communication links (more users) can be established with a Frequency Hopping (FH) scheme.

First of all, the communication between any 2 users is established through a pattern of hopping frequencies. Another pair of users can establish communication using another set of frequencies (or hopset) within the same band as long as the frequencies within the 2 sets are orthogonal and do not cause co-site interference. This can be extended to any number of users in the system.

The key is that the frequencies within the hopsets can be the same. But at any one time, the frequency being used by 1 pair of users must not be used in another communication link. In this way, more users can be serviced and there's an increase in capacity.

Hope it helps.

 

[artem]

Mainly destined to imrpiove speech quality it will improve channel drop rate - so this is the only way where hooping can increase capacity . If you are employed by wireless operator and can play with this parameter - take one day snapshot of drop statistics with hopping on and off and compare results .