4. Results and analysis
5.3 Further work and other analyses
This study has investigated the main cost differences of utilising 700 MHz against the three main demand scenarios and for several assumptions regarding the growth in network capacity. There are many possible combinations of inputs that could have been analysed to determine more specific differences of how 700 MHz could provide benefits or not in the future.
The following sections describe how a difference in some of the key input assumptions could lead to an alternative outcome of using 700 MHz.
5.3.1 Impact of the differences between demand assumptions
The demand assumptions in the study are what drives the size and shape of the capacity network built by the model. We modelled all critical demand cases in the study to
determine a variety of sensitivity cases and the extremes. However, some other corner points could be explored by maintaining the mid capacity cases and varying demand. This will highlight the impact of timing (amongst other things) by introducing 700 MHz at earlier points in the timeframe.
5.3.2 Alternative offload assumptions
In the study we assumed that offload provides an alternative means of transferring mobile network traffic to the fixed network. A shift in the assumptions based on consumers’
willingness to pay for devices or poor quality of service owing to unlicensed and crowded spectrum, could lead to higher costs to the mobile network.
No explicit spectrum allowance is made for offload. It is assumed that offload devices would either operate in licence-exempt spectrum (as in the case of Wi-Fi) or in licenced spectrum in a way which does not significantly increase the overall spectrum requirement, either by successfully coordinating with macrocells in the same channels or else in
dedicated channels – either operator-specific or shared across the market – with a high level of frequency reuse.
Given these open questions, this represents an area where further study should be conducted. Nevertheless, we have accounted for levels of offload which are consistent with current trends and note that even if offload levels were half those which we have assumed, this would be well within the range of the demand scenarios we have examined.
5.3.3 Uncertainties in spectrum availability
In the study we assumed there would be availability of spectrum across 17 different frequency bands. These bands were identified on the basis that they were suitable for mobile use and were (or could be) standardised and harmonised. However, it was recognised there are some uncertainties surrounding some of the bands identified.
In particular, there is uncertainty regarding quantity and timing of the availability of the public sector and current non-mobile allocated bands which represented 40% of total available spectrum for the study.
The assumptions for these spectrum bands were based on the latest public information available. However, by adjusting the quantity and timing of the availability of these bands could impact the results particularly in high demand cases when the spectrum bands
5.3.4 Assumptions on a single network
In order to simplify the modelling we assumed a single operator would deliver mobile broadband services over two shared networks with traffic equally split between them.
However, this assumption may impact the costs to a single mobile operator since mobile operators will base the value of 700 MHz spectrum their own spectrum and site portfolios.
Additionally, the assumption for the evolution towards site sharing can also impact the costs because it assumes no new individual operator sites will be built and in practice that may not be the case.
5.3.5 Practicality and challenges for deploying small cells
We assumed that small cells could be deployed anywhere within the study area without consideration for the practicalities and limitations in doing so. Small cells still require planning permission and coordination and a proportion of the small cells deployed in the study area might not be deployed in practice or might not be as well-located as we have assumed.
A useful analysis would be to understand the impact of suboptimal placement of small cells.
5.3.6 Assumptions on uniform distribution of demand
We assumed that demand was not uniformly distributed across the study areas so as to represent a more practical and realistic environment. It could be argued that if demand were more uniformly distributed, which as discussed in Annex A5 is moving in that
direction, the utility of 700 MHz would be increased due to the more consistent and spatial spread of demand.
5.3.7 Assumption on indoor/outdoor demand split
The split between amount of indoor and outdoor demand was informed by current analyst data which illustrated the majority of demand consumption indoor with that trend set to continue in the future. A sensitivity analysis of a different indoor/outdoor demand split would potentially highlight the effects between lower frequency spectrum and higher frequency spectrum and difference in the ability to serve the indoor demand.
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Techniques for increasing the capacity of wireless broadband networks: UK, 2012-2030
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