stds-80220-requirements: Section 4.1.2 Spectral Efficiency
Folks,
I was on tap for updating the text in this section
to reflect the last requirements call. The general consensus on
the call was to move forward with specifying a definition that
would also lead to a baseline configuration for the evaluation
group. (Please note previous recent text from Dan, Faroukh,
and Samir on this section)
Current text
Sustained spectral efficiency is computed in a loaded multi-cellular network
setting. It is defined as the ratio of the expected aggregate throughput
(taking out all PHY/MAC overhead) to all users in an interior cell divided
by the system bandwidth. The sustained spectral efficiency calculation
shall assume that users are distributed uniformly throughout the network.
[Downlink > 2 bps/Hz/sector]
[Uplink >1 bps/Hz/sector]
Proposed Text
Sustained spectral efficiency is computed in a loaded multi-cellular network
setting. It is defined as the ratio of the expected aggregate throughput
(taking out all PHY/MAC overhead) to all users in a sector divided
by the system bandwidth (the aggregate spectral allocation in use across
the entire system). The sustained spectral efficiency calculation shall
assume that users are distributed uniformly throughout the network
and shall include a specification of the minimum expected data rate/user.
A fair comparison of the spectral efficiencies of different air interfaces
can best be achieved for a single specified baseline configuration. To
facilitate the subsequent evaluation of different proposals for the 802.20
air interface, the spectral efficiency of the 802.20 air interface shall
be quoted as b/s/Hz/sector for a three sector baseline configuration.
Within this subsequent evaluation, proposals may submit respective
deployment models over and beyond the base configuration.
Consistent with the PAR requirement that is stated on a per cell basis and
the definitions shown in Appendix A, the sustained spectral efficiency of
the 802.20 air interface shall be greater than 1 b/s/Hz/sector.
Rationale
This proposal captures the need for a baseline comparison methodology
for ease of evaluating various proposals. By establishing a baseline
three sectored configuration, we also finesse the subtleties in
the per cell or per sector nature of the definition of spectral
efficiency.
[NOTE: The definition of "cell" in Appendix A states, "The term "cell"
refers to one single-sector base station or to one sector of a base
station deployed with multiple cells." As such, the PAR requirement of
1 bits/sec/Hz/cell is equivalent to 1 bits/sec/Hz/sector.
The value established in the PAR and by the definition in the
appendix through the definition: "Spectral efficiency: Spectral
efficiency is measured in terms of bits/s/Hz/cell. (In the case
of a sectorized configuration, spectral efficiency is given as
bits/s/Hz/ sector.)"
The current text in the Requirements document -- Version 8c
has:
downlink > 2 b/s/Hz/sector, and
uplink > 1 b/s/Hz/sector
While these values are proposed in the current document. I could
not find any rationale for them on the list. The Requirements Group
still needs to agree on target values for spectral efficiency.
]
Mike