On Aug 20, 8:13&#4294967295;am, "hardheart" <hardheartcn@n_o_s_p_a_m.yahoo.com.cn>
wrote:
> Dear All,
>
> I am doing a project of GSM baseband signal processing and now facing the
> problem of how to reduce the cochannel and adjacent channel interference.
> The main modules I have implemented are channel estimation and MLSE
> equalizer, but I find the MLSE performance in terms of Bit Error Rate is
> not good enough when interference exits.
>
> I have three questions here.
>
> 1, some internet articles say that to use a noise whitening filter (not
> implemented in my design yet) after matched filter (done already in my
> design) can reduce interference. Is it a correct way or standard method for
> mitigating GSM interference?

Yes. Because MLSE works best for white noise. If you do not have white
noise, then it is not maximum likely any more.


> 2, what is the typical anti-interference algorithm used in a commercial
> mobile phone?

For out-of-band interference, use filter. But I do not think it will
be a big issue as the interference is presumably very small.
For in-band  interference, other people already suggested SAIC, you
can find a lot of references about the algorithm.
>
> 3, can anybody give a useful link on algorithms on anti-interference/noise
> whitening filter?
>
> hope somebody can help. Thank you.
>
> Richard

Search SAIC. The technique for suppressing co-channel is quite mature. 

cfy30

>On Aug 20, 8:13=A0am, "hardheart" <hardheartcn@n_o_s_p_a_m.yahoo.com.cn>
>wrote:
>> Dear All,
>>
>> I am doing a project of GSM baseband signal processing and now facing
the
>> problem of how to reduce the cochannel and adjacent channel
interference.
>> The main modules I have implemented are channel estimation and MLSE
>> equalizer, but I find the MLSE performance in terms of Bit Error Rate
is
>> not good enough when interference exits.
>>
>> I have three questions here.
>>
>> 1, some internet articles say that to use a noise whitening filter (not
>> implemented in my design yet) after matched filter (done already in my
>> design) can reduce interference. Is it a correct way or standard method
f=
>or
>> mitigating GSM interference?
>>
>> 2, what is the typical anti-interference algorithm used in a commercial
>> mobile phone?
>>
>> 3, can anybody give a useful link on algorithms on
anti-interference/nois=
>e
>> whitening filter?
>>
>> hope somebody can help. Thank you.
>>
>> Richard
>
>For co-channel interference, search on "GSM Multiuser Detection" --
>there is plenty of info. It's not an easy problem though.
>
>John
>

On Aug 20, 8:13&#4294967295;am, "hardheart" <hardheartcn@n_o_s_p_a_m.yahoo.com.cn>
wrote:
> Dear All,
>
> I am doing a project of GSM baseband signal processing and now facing the
> problem of how to reduce the cochannel and adjacent channel interference.
> The main modules I have implemented are channel estimation and MLSE
> equalizer, but I find the MLSE performance in terms of Bit Error Rate is
> not good enough when interference exits.
>
> I have three questions here.
>
> 1, some internet articles say that to use a noise whitening filter (not
> implemented in my design yet) after matched filter (done already in my
> design) can reduce interference. Is it a correct way or standard method for
> mitigating GSM interference?
>
> 2, what is the typical anti-interference algorithm used in a commercial
> mobile phone?
>
> 3, can anybody give a useful link on algorithms on anti-interference/noise
> whitening filter?
>
> hope somebody can help. Thank you.
>
> Richard

For co-channel interference, search on "GSM Multiuser Detection" --
there is plenty of info. It's not an easy problem though.

John

hardheart wrote:

> Dear All,
> 
> I am doing a project of GSM baseband signal processing and now facing the
> problem of how to reduce the cochannel and adjacent channel interference.
> what is the typical anti-interference algorithm used in a commercial
> mobile phone?

1. The adjacent channel is simply filtered out.

2. The nonlinear effects between the adjacent channels could be a big 
problem. Therefore the system is planned in such way so the adjacent 
channels are never used within a cluster or a group of neighboring clusters.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

On Fri, 20 Aug 2010 07:13:09 -0500, "hardheart"
<hardheartcn@n_o_s_p_a_m.yahoo.com.cn> wrote:

>Dear All,
>
>I am doing a project of GSM baseband signal processing and now facing the
>problem of how to reduce the cochannel and adjacent channel interference.
>The main modules I have implemented are channel estimation and MLSE
>equalizer, but I find the MLSE performance in terms of Bit Error Rate is
>not good enough when interference exits.
>
>I have three questions here.
>
>1, some internet articles say that to use a noise whitening filter (not
>implemented in my design yet) after matched filter (done already in my
>design) can reduce interference. Is it a correct way or standard method for
>mitigating GSM interference?
>
>2, what is the typical anti-interference algorithm used in a commercial
>mobile phone?
>
>3, can anybody give a useful link on algorithms on anti-interference/noise
>whitening filter?
>
>hope somebody can help. Thank you.
>
>
>Richard

For out-of-band or band edge interference, filtering is always a good
strategy.   For in-band interference it's a much more difficult
problem.


Eric Jacobsen
Minister of Algorithms
Abineau Communications
http://www.abineau.com

Dear All,

I am doing a project of GSM baseband signal processing and now facing the
problem of how to reduce the cochannel and adjacent channel interference.
The main modules I have implemented are channel estimation and MLSE
equalizer, but I find the MLSE performance in terms of Bit Error Rate is
not good enough when interference exits.

I have three questions here.

1, some internet articles say that to use a noise whitening filter (not
implemented in my design yet) after matched filter (done already in my
design) can reduce interference. Is it a correct way or standard method for
mitigating GSM interference?

2, what is the typical anti-interference algorithm used in a commercial
mobile phone?

3, can anybody give a useful link on algorithms on anti-interference/noise
whitening filter?

hope somebody can help. Thank you.


Richard