02 October 2006P1901_0199_r0
IEEE P1901
Draft Standard for Broadband over Power Line Networks:
Medium Access Control and Physical Layer Specifications
Date: 2006-10-02
Author(s):
Name / Company / Address / Phone / email
Jean-Philippe Faure / Ilevo-Schneider Electric Powerline Communications / 59, Chemin du vieux chêne, F38240 Meylan, France / +33 (0)4 76 60 59 56 /
- Analysis of the Coexistence/Interoperability requirements and the interactions with the IH and AC requirements.
No CX requirements prevents us from selecting interoperable P1901 In-Home and P1901 Access PHYs. See CX Group 51 UCX2.11r0. The BPL coexistence/interoperability mechanism shall support the use of interoperable Access and In-Home PHY layers to minimize channel resources usage inefficiencies and transcoding requirements.
If the group selects interoperable P1901 In-Home and P1901 Access PHYs:
-CX Group 1 UCX1.1r0 and CX Group 9 UCX1.9r0 and UCX1.10r0 say that the CX mechanism activates the channel resources sharing mechanism when a minimum threshold of interference is met. This means that, in the case of interoperable P1901 IH and P1901 AC PHYs, since there will be no interference between systems, the sharing of channel resources between the P1901 systems will not be handled by the CX mechanism but by the P1901 IH and AC PHYs and MACs. This is an issue for the IH and AC clusters since, at the moment, there are no rules on channel resource sharing in the IH and AC clusters.
-The impact of the channel resources will be less than 5%. P1901 IH and P1901 AC are under no coexistence conditions, so the transmission and the detection of coexistence signals will use no more than 5 % of the channel resources in time and/or frequency. See CX Group 18 UCX1.21r0.
-For the same reason (no coexistence conditions), the impact on the performance (throughput and latency) will be minimal. See CX Group 18, UCX1.22r0.
The CX requirements does not prevent from selecting P1901 IH and P1901 AC MACs and PHYs with a with centralized controller, for example implementing Polling mechanisms or Beacon mechanisms. See CX Group 31 UCX1.31r0: The CX mechanism shall efficiently work with centralized controller networks such as networks implementing Polling mechanisms or Beacon mechanisms.
Two requirements does not apply to the CX mechanism but to the P1901 In-Home and P1901 Access.
-CX Group 46 UCX2.7r0: The Access and In-home BPL MAC and PHY shall have the same QoS parameters.
-CX Group 47 UCX2.8r0: The Access and In-home BPL MAC and PHY shall have compatible QoS management schemes.
Conclusion:
-The CX mechanism is defined as an interface that can be used by any technologies that want to coexist with each others, in particular with the 1901 technology (AC and IH PHYs and MACs).
-The CX mechanism can be used as the interface between the 1901 IH and 1901 AC devices but not necessarily. The interface between the 1901 IH and the 1901 AC devices can be different (interoperability).
- Wrap up for a common understanding
CX cluster: requirements for an interface that can be used by any technologies that want to coexist with each others, in particular with the 1901 technology (AC and IH PHYs and MACs). This interface can also, but not necessarily, be used between 1901 IH and 1901 AC devices.
It seems assumed that all 1901 devices will embed the CX mechanism. Can the group confirm?
IH cluster: PHY + MAC requirements for IH devices
AC cluster: PHY + MAC requirements for AC devices
An action item is open on the clarification of the applicability of Access and In-Home Cluster Requirements. Documents P1901_FTR_032_r0_ac-ih_cluster_applications.doc and P1901_FTR_036_r0_matrix classes of devices applicable requirements.xls.
- New issues identified / proposed actions
Issue 1. No rules for sharing the channel resources between the 1901 IH and the 1901 AC devices in the case that another mechanism than the CX mechanism is selected as interface between the 1901 IH and the 1901 AC devices.
Proposed action: copy the channel resources sharing rules of CX Group 44 UCX2.5r0 in both the IH and the AC clusters:
CX Group #44. Under coexistence conditions with insufficient resources for all, fair and intelligent allocation of resources between the Access system and the group of In-home systems
Reference / Requirement / Notes (informative)FTR SG / UCX2.5r0 / In case the access system coexists with one or more in-home systems and the total of channel resources needed by the systems exceeds the total amount available, the coexistence mechanism shall allocate the channel resources to systems according to the following rules:
-Provide all channel resources requested by the Access system as long as it needs less than 50% of the total amount available
-Provide all channel resources requested by the group of In-Home systems as long as they need in total less than 50% of the total amount available
Issue 2: the CX Group 46 UCX2.7r0 and CX Group 47 UCX2.8r0 requirements are actually AC and IH requirements and not CX requirements.
Reference / Requirement / Notes (informative)FTR SG / UCX2.7r0 / The Access and In-home BPL MAC and PHY shall have the same QoS parameters.
FTR SG / UCX2.8r0 / The Access and In-home BPL MAC and PHY shall have compatible QoS management schemes.
Proposed action: delete the CX Group 46 UCX2.7r0 and CX Group 47 UCX2.8r0 requirements in the CX clusters. There are already copied in both the AC and IH clusters.
Submissionpage 1Jean-Philippe Faure, Ilevo