# A Spectrum Management Platform Architecture to Enable a Sharing Economy in 6G
## 2 Literature Review  
### Traditional Spectrum Allocation and Sharing  
Currently, spectrum allocation is still dominated by administrative allocation controlled by national regulators. These regulators also stipulate static conditions on how operators can utilise the allocated spectrum, expressed in offered capacity, coverage, etc. although these conditions do not always reflect the real requirements of wireless users [6].  
An alternative approach is to apply the laws of the market to incentivise a fairer and more consumer-oriented allocation of the spectrum resource. Here, the right to operate blocks of radio frequency will be granted to operators who value this spectrum the most, for instance as determined by auctions. This approach has been very successful in the 3G, 4G, and 5G eras. In LSA [7], market-based allocations allow an operator to lease some of its frequencies to a third party, thus introducing more flexibility in the dynamic of spectrum allocation.  
A variety of LSA is CSA [3]. Here, multiple operators share access to the same block of the spectrum but in a coordinated and managed way. An example is club licencing: A licence is given to a club of operators. An operator can use the whole block if it is the sole provider in an area. When another club member wants to operate in that area too, it has the right to a fair share of the block. This is a form of dynamic spectrum sharing, but time scales are measured in weeks or months rather than minutes or hours. CBRS has also recently been authorised for use in the United States. Here, a three-tiered spectrum authorisation framework accommodates various commercial models simultaneously for the 3.5 GHz band [8]. The highest tier is Incumbent Access, which reserves a part of the band for radar operation, similar to administrative allocation. In the second tier, Priority Access, sub-bands of 10 MHz are licenced commercially, such as market-oriented allocation. In the General Authorised Access, users are permitted to use any portion of the band not assigned to higher tier users but still need to acquire a temporary low-cost license for use of the spectrum in, e.g., a single building.  
A commonality between these spectrum-sharing models is that they rely on spectrum uniquely allocated to a major licence holder which has primary rights to it in a semi-static way, regardless of whether that spectrum is actually used or not. This inevitably leads to spectrum waste, where the demand is low, and spectrum congestion, where the demand is high, and unnecessary costs either way. The only alternative able to address this problem is to use the so-called unlicensed bands. Here, everybody has the fundamental right to access the spectrum anytime and anywhere but must accept possible interference from other users. Most protocols using these bands typically have \"listen-before-talk\", \"clear channel assessment\" and \"duty-cycle muting\" mechanisms included to allow other devices to access the medium too [9; 10; 11], but when congestion becomes eminent, they all apply the law of the jungle resulting in only losers [4]. Moreover, works in [12; 13] illustrate how multiple systems that coexist in unlicensed bands interfere with each other due to asymmetries and selfish system behaviour. The authors then propose punishment strategies based on game theory which allow for fair and efficient use of the band. However, the solutions are not evaluated in realistic scenarios involving wireless technologies.