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Hi Sungcheol, please see my
opinion on your comment to question 3 below. Thanks, Eldad Office +1 631 622
4134 Mobile +1 631 428 4052 Based in NY area From: Chang, Sungcheol
[mailto:scchang@etri.re.kr] Hi all, Please see my comments to question
3. Best regards, Sungcheol Chang, Ph.D. Mobile Access Technology Research Team, ETRI From: Zeira, Eldad
[mailto:Eldad.Zeira@INTERDIGITAL.COM] Hi Mingtuo, Haiguang Thanks for this discussion. I
mostly agree with Haiguang's opinion but have one question for clarification
and several suggestions. Eldad Office +1 631 622
4134 Mobile +1 631 428 4052 Based in NY area -----Original Message----- Dear Ming-Tuo and all, Thanks very much to Ming-Tuo
bring this topic to the group. It is very important to have a
common understanding these issues. I try to reply the questions
based on my understanding. Please see my answer inline. Regards. Haiguang -----Original Message----- From: Ming-Tuo ZHOU
[mailto:mingtuo@nict.com.sg] Sent: Thu 4/21/2011 6:20 PM To:
STDS-802-16@LISTSERV.IEEE.ORG Subject: [STDS-802-16]
[802.16n][DC] Discussion on definition of HR-MS DC and Forwarding to Network Dear 16n participants, I'd like to trigger discussion
of definition of HR-MS direct communication and HR-MS forwarding to network,
since from many discussions it seems there are some confusion regarding them.
In my opinion, it is necessary to have a clear common understanding of these
two functions for development of technical details in a more smooth way. Anyone
is welcome to bring his/her understanding of these two functions by replying
this email. I hope after several rounds of email discussion, we can achieve
some consensus regarding these two functions. The discussion may be started by
answering follow questions: 1. what is HR-MS direct
communication (DC)? Haiguang: HR-MS direct
communication means, the two HR-MSs involved in the communication
are the producer and consumer of the data packets. That is, the source HR-MS
pass the data packet down from upper layer to MAC and the destination HR-MS
pass the packet to upper layer from MAC after receiving from the air.
Clarification: the producer and consumer here are from the view of MAC. It does
not mean the packet is originated from the source HR-MS and terminated at the
destination HR-MS. Eldad: suggest the following
text (editorial cleanup, I think it means the same) The two HR-MS that are in
direct communications with each other are the source and the sink of data.
Packets are passed from upper layers to MAC at the source and back to upper
layers at the sink HR-MS. 2. what is HR-MS forwarding to
network (FTN)? Haiguang: HR-MS forwarding means
the forwarding HR-MS either forwards the data packet to
HR-BS or to the HR-MSs that access the network via the forwarding HR-MS.
The forwarded packet will not be passed to upper layer. Instead, it is forwarded
to
next hop at MAC layer. Eldad:
again I agree with the principle and suggest the following wording: An
HR-MS that forwards data to infrastructure node or to another forwarding HR-MS
that is attached to an infrastructure node (if multi-hop is supported) does so
without passing any data to or from higher layers. 3. what's difference between
HR-MS DC, HR-MS FTN, and HR relay/local forwarding? Haiguang: The differences are:
* For HR-MS DC, at the source HR-MS, the data packets are from upper layer and
are passed
to upper layer protocol at the destination HR-MS.
* For HR-MS FTN, the data packet is forwarded to next hop at MAC layer. The
data packets are
not handled by upper layer protocol. HR-MS who forwards data packet is still an
HR-MS. It
only has a very simple relay function and can only support very few nodes, one
or two.
From other HR-MSs' view, HR-MS performing the relay function is still an HR-MS.
HR relay is a kind of
infrastructure station designed for the purpose of relay. It is complex and
like a BS. It is designed to support many MS in network access. * Local forwarding means the
infrastructure station between MS and BS forwards data packets from downstream
HR-station to destination HR-MS without passing it to upstream infrastructure
stations. A general case is a HR-RS
forwards the data packets from one of its HR-MS (source) to another HR-MS which
is the destination. Eldad:
- Not
sure what is the meaning of "From other HR-MSs' view, HR-MS performing the
relay function is still an HR-MS." - could you please clarify? -
From the SRD, an HR-RS is " A relay that
complies with the requirements for relays in this amendment". This
is an amendment to 802.16n or 2009, which means that an HR-RS is an RS or ARS
as amended by 802.16n. I don’t think we need to define it any further,
although we'll need to specify how to implement the requirements we have agreed
to in the SRD. Haiguang: My meaning is that the HR-MS
should aware that the MS forwards data control for it is an HR-MS. It is not a
relay station. Sungcheol
Chang: From the discussions and the
definitions in the 16n SRD, the definitions of direct communication and HR-MS
forwarding are clearly different in respect of data flow. But I still confuse that the
technical difference between HR-MS forwarding and HR-RS functionalities. Even though HR-RS is an
infrastructure node and HR-MS is a user terminal in nature, I think their names
are not important. If devices should receive packets transmitted by HR-MS, a
receiving function within devices is to receive the packets. Whatever the
devices are called like HR-MS or HR-RS. Their receiving functionalities are
similar in nature. I want to know what the
technical differences are because we are in developing the AWD text proposal. What happen if we replace 1)
HR-MS with HR-RS 2) forwarding HR-MS with HR-RS in the following definition? The definition of forwarding:
"An HR-MS that forwards data to infrastructure node or to another
forwarding HR-MS that is attached to an infrastructure node (if multi-hop is
supported) does so without passing any data to or from higher layers." What happen if we assume a
forwarding HR-MS as a HR-RS serving one sub-ordinate HR-MS only? Under this
assumption, please list the technical difference between a forwarding HR-MS and
a HR-RS serving one sub-ordinate HR-MS only. Personally, if we achieve a
forwarding HR-MS functionality with simple modification of HR-RS including
signaling procedures, I prefer the modification rather than defining new
function and transmission schemes Also I’d like to know
what forwarding HR-MS is more simple than HR-RS. I understand that HR-RS has
more functionalities than HR-BS and HR-RS is a infrastructure node. There are
two views about complexity. The one is hardware complexity because HR-RS is
designed to serve multiple HR-MS. This complexity is not important issue in
respect of functionalities. The other is functional complexity. HR-RS support
two interfaces for relay operation: 1) interface between HR-BS and HR-RS, 2)
interface between HR-MS and HR-RS. It’s clear that forwarding HR-MS has
two interfaces also. The relay specification describes relay function in HR-RS,
which is required to relay data and packets to HR-BS or HR-MS. Even though more
than HR-BS functionalities, the HR-RS functionalities are selected ones
required for relay operation. From this understanding, please list what
forwarding HR-MS is more simple than HR-RS. It will help me to understand what
the forwarding function is. [Eldad] the SRD states clearly that forwarding is a
functionality of the HR-MS not the HR-RS (see excerpt below). Obviously there
will be similarities between the forwarding function and a relay function as
both support 2 interfaces. That doesn’t mean that the two are the same. The
amount of similarity will be determined by technical contributions. For example
only, frame structure can resemble relays (i.e. transmission in both UL and DL
zones) or be in UL only (as some proposed). 6.1.3.2
HR-MS forwarding to network
HR-MS forwarding is defined as the case where the
origination and termination of data are at the HR-MS and network respectively
and vice versa. HR-Network shall support HR-MS forwarding of user data and
control signaling between HR-MS and HR-BS and between HR-MS and HR-RS.
The control signaling and data transmission for the HR-MS to HR-MS direct link
shall at least be capable of operating within the frequency band that the HR-BS
operates. An association establishment shall be supported. Finally, the following is
expected to be made: [Consensus:
] Thank you very much. Best regards, Ming-Tuo Zhou 16n DC RG co-chair |