[STDS-802-16-MOBILE] [Handoff] Multiple frequency assignment for the same sector (BS)
Vladimir,
May I add the following to the discussion. I think that while there are items that may need addressing, there are other items that are possibly being broken in the development of .16e.
First I think it is necessary to discuss what the standard regards as a base station.
Could I first provide an example: This is meant to be a plan view of a BS site (marked #) with 4 ideal 90 degree antennas,
each with 2 frequencies (F1 to F4).
|
|
F1,F2 | F3,F4
|
|
------------#------------
|
|
F3,F4 | F1,F2
|
|
The first question is how many basestations does it take to provide this coverage?
My understanding is that through use of multiple PHY and MAC, the answer is any number between 1 and 8, based on groups of either 1, 2, 4 or 8, and that for fixed deployments it is up to the BS equipment manufacturer as to which of these options is implemented.
There are problems with broadcast CIDs being common, but I think this is implementational: this just means that the MAC needs to be multi-threaded in order to distinguish the fixed CIDS on a per sector, per frequency basis.
My understanding is that the way the BS distinguishes the sectors/frequencies is through the Downlink Channel ID and Uplink Channel ID fields in the DCD/UCD messages. In that way a BS (with a single BS ID) providing, for example both F1 and F2 in a single sector can advertise the availability of the other frequencies.
My expectation is that in a fixed deployment each sector would transmit DCD messages advertising the set of frequencies available to the SS (one per (Downlink/Uplink) Channel ID).
This idea needs generalising in .16e, but there does seem to be a conflict between the view outlined above and details in the compressed map format (Compressed DL-MAP message format, e.g. [802.16-REVd/D5-2004] Table 303), where the Sector ID is defined as the lowest 8 bits of the BS ID. If the lowest 8 bits of the BSID are used to represent sectors, then this precludes the possibility of constructing a BS that has a single BSID for the site (and using 8 Downlink (Uplink) Channel IDs to distinguish the channels).
In the case of mobile, and possibly even for fixed deployments, there is the need to provide information about the frequencies available in the adjacent cells. Surely the channel ID is the basis on which this could be achieved. Additional information may then be provided in the DCD/UCD associated with the channel ID that can assist hand-over within a BS, where the basestation to be implemented as a single entity. Then .16e could adjust the scope of channel IDs to facilite co-ordination between multiple basestations to assist handover.
Comments very welcome.
Regards
David
-----Original Message-----
From: owner-stds-802-16-mobile@LISTSERV.IEEE.ORG
[mailto:owner-stds-802-16-mobile@LISTSERV.IEEE.ORG]On Behalf Of Vladimir
Yanover
Sent: 09 June 2004 17:51
To: STDS-802-16-MOBILE@LISTSERV.IEEE.ORG
Subject: Re: [STDS-802-16-MOBILE] [Handoff] Multiple frequency
assignment for the same sector (BS)
This isssue is not so simple as may look.
I am not sure that current 802.16 standard supports having
several [frequency] channels for a single MAC instance
[I think, it does not]. Large part of the standard was
written under assumption that e.g. same broadcast messges
[like DL-MAPs] can be received by all SSs under BS control.
If we want to make multi-frequency operations [per single MAC instance]
possible, we have to examine very carefully the whole text of the standard
to see that it is consistent.
As REVd is closed, it might be a problem to develop [clean up] all topics
needed for such functionality.
Vladimir
-----Original Message-----
From: Ken Stanwood
To: STDS-802-16-MOBILE@listserv.ieee.org
Sent: 6/8/2004 7:21 PM
Subject: Re: [STDS-802-16-MOBILE] [Handoff] Multiple frequency assignment
for the same sector (BS)
Be certain to add new fields as TLVs in a way that older (16d) equipment
that receive the fields can ignore them and still operate correctly as
fixed (rather than mobile) equipment.
Ken
_____
From: owner-stds-802-16-mobile@LISTSERV.IEEE.ORG
[mailto:owner-stds-802-16-mobile@LISTSERV.IEEE.ORG] On Behalf Of Mary
Chion
Sent: Monday, June 07, 2004 11:04 PM
To: STDS-802-16-MOBILE@LISTSERV.IEEE.ORG
Subject: [STDS-802-16-MOBILE] [Handoff] Multiple frequency assignment
for the same sector (BS)
All,
This is a recap of the discussion for the multiple frequency assignement
of the same sector. There are two options to handle this configuration:
Option 1:
Change the definition of a sector to allow multiple frequency
assignments. This implies to change DCD message to include multiple
FA_IDs and allow a handover type of intra-sector inter-frequency
handoff.
Option 2:
The sector definition remains the same: a sector of single frequency
assignment. The DCD message remains to include one FA_ID. For multiple
frequency assignement for the same sector, each frequency channel will
be the treated as a sector, hence, the identity of a sector should be
defined as: BS ID, sector ID and FA_ID. The handover between frequencies
can be treated the same as inter-sector inter-frequency handoff.
Please provide your comments and hopefully, we can agree on one option.
Mary Chion
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