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Re: [STDS-802-16-MOBILE] [Handoff] Virtual Soft Handoff (Soft Swi tching)



Title: Message
 
That sounds like a reasonable proposal to me.
 
Generally, I am wondering more about exactly what type of applications, especially in the IP context will warrant the different types of HOs we outlined. It would be good to have an explicit categorization, consisting of  groups of systems functions, within each of which we would outline the types of IP traffic, their performance requirements, the types of HOs desired, etc. Those classes could then be the basis for profiles defined by the standard. Nor all systems would need to support all profiles. So, simpler, easier to deploy and less expensive systems ( still supporting mobility) would be possible.. Would this make sense?
 
Branislav
-----Original Message-----
From: owner-stds-802-16-mobile@LISTSERV.IEEE.ORG [mailto:owner-stds-802-16-mobile@LISTSERV.IEEE.ORG]On Behalf Of Mo-Han Fong
Sent: Monday, June 07, 2004 10:06 AM
To: STDS-802-16-MOBILE@LISTSERV.IEEE.ORG
Subject: Re: [STDS-802-16-MOBILE] [Handoff] Virtual Soft Handoff (Soft Swi tching)

Phil and all,
 
To avoid any potential future confusion when we deal with interoperability issue with other standards, I suggest to use Soft Handover to refer to macrodiversity as currently defined in 3GPP2 1xRTT/1xEV-DV standards and 3GPP UMTS standards.
 
For the virtual soft handover (soft switching) case Irving has suggested, we can use the term 'Fast BS Switching' similar to what is used in 1xEV-DV (i.e. fast cell switching).
 
Note that the above terms (SHO, fast BS switching) are referring to radio operation. We can separately define the different levels of transfer or sharing of upper-layer context as in the scope outline document (C802.16e-04_105_0601.doc) which can be applied to different handoff scenarios.
 
Comments?
 
Regards,
 
Mo-Han
-----Original Message-----
From: Itzik Kitroser [mailto:itzikk@RUNCOM.CO.IL]
Sent: Monday, June 07, 2004 12:13 PM
To: STDS-802-16-MOBILE@listserv.ieee.org
Subject: Re: [STDS-802-16-MOBILE] [Handoff] Virtual Soft Handoff (Soft Switching)

Phil, all,

 

I believe that we can go into two possible directions here:

  1. Either well define the terminology, which I believe Phil did well (although some additions are required).
  2. Acknowledge the fact the some terminology is used in other standards, reuse their meaning (like soft handoff) and define new scenarios special to .16 networks.

 

I think that both approaches will reduce possible ambiguity. The advantage of the second approach is that people coming from different mobile world and skip the definitions part, will not misinterpret our terminology.

Don't know what option is better.

 

Itzik.

 

-----Original Message-----
From: owner-stds-802-16-mobile@LISTSERV.IEEE.ORG [mailto:owner-stds-802-16-mobile@LISTSERV.IEEE.ORG] On Behalf Of Phillip Barber
Sent: Monday, June 07, 2004 2:22 PM
To: STDS-802-16-MOBILE@LISTSERV.IEEE.ORG
Subject: Re: [STDS-802-16-MOBILE] [Handoff] Virtual Soft Handoff (Soft Switching)

 

This is the mechanism I originally envisioned when devising HO methodology language and structure in the document.  Supporting this mechanism would be much easier than re-writing the document to support a macrodiversity/synchronized transmission Soft HO mechanism.  But we should be aware that any macrodiversity benefit will be lost using this mechanism.

 

On a related note, this is what I was talking about when discussing differentiating concept ('Soft Handoff') from the specific mechanism used to achieve that concept or enhance reliability (pre-HO context transfer, fast-switching, macrodiversity, etc...).  The EVDO mechanism is referred to as 'Virtual Soft Handoff' yet has no element of macrodiversity--the primary criteria cited by the group on the June 3 conference call as defining 'Soft Handoff' (by the way, we should be using 'handover' here, not 'handoff').

 

I once again reiterate these definitions:

 

Hard-handover: a handover occuring without transfer of MSS service and operating context prior to MSS network re-entry at the new attachment point

Soft-handover: a handover occuring with transfer of MSS service and operating context prior to network re-entry at the new attachment point such that the MSS enjoys  persistent context and continuity of service across handover

Soft-handover with macrodiversity: a handover occuring with transfer of MSS service and operating context prior to MSS network re-entry at the new attachment point, with two or more BS providing synchronized transmission of MSS downlink data during the handover interval, such that the MSS enjoys persistent context and continuity of service across handover

 

Thanks,
Phil

----- Original Message -----

From: Irving Wang

Sent: Sunday, June 06, 2004 10:51 PM

Subject: [STDS-802-16-MOBILE] [Handoff] Virtual Soft Handoff (Soft Switching)

 

Hi,

Soft Handoff provides gains for real-time transmission application, thus, we strongly support it being accepted in the standard.

However, system complexity may increase dramatically and H-ARQ may need to be turned off to support Soft Handoff. For non-real-time transmission, the loss may outweigh the benefit by using soft Handoff.

Therefore, in cdma2000 1XEV-DO system, virtual soft handoff (or soft switching) is used instead of Soft Handoff.

In virtual soft handoff (or soft switching), only one BS in the active list with the best pilot strength transmits at any moment.

We think it will provide the following benefit:

 

1. It provides diversity gain by allowing fast switching of data transmission from BS to another BS.

2. It can fit into both OFDM and OFDMA PHY layer without much change

3. Since only BS is transmitting at any given time, the schedule of the BS can be more flexible and optimized than in SHO (no data synchronization issue to worry about)

4. It can easily support data connection with H-ARQ

5. It won't take up additional air link capacity/resource as in SHO case.

 

We would like to propose the virtual soft handoff coexist with soft handoff in the standard to provide more flexibility.

 

Any opinion?

 

Best regards,

 

 

 

Irving Wang, Ph. D.

Director, Standards

& 3G Technologies

ZTE San Diego