1. PURPOSE OF THE SYSTEM FUNCTION (10 lines)
The purpose of our system function is to simulate the sub-carriers allocation for packets transmission in the case of LTE communication. The system will focus on ressources allocation scheduling in the case of downlink communications. Several parts will be implemented:
- a buffer that recovers the datas incoming on the station (as an array or a multiple queues assigned to each user)
- a scheduler that will handle the allocation of Ressources Block Groups (a group of ressources blocks, each ressource block allocated corresponds to a set of sub-carriers) to users to whom some datas in the buffer belong
- a mapper that will assign the ressource blocks available on the carrier to the ressource block groups
- maps of ressources blocks that represent the transmission channel and the carried datas
- simulated receiving clients and simulated data to exchange
- a tuned clock to synchronize the frames emission
The scheduler may use three scheduling techniques, either combined or just one at a time. Those scheduling algorithms are Max-CQI, Proportional Fair and Round-robin.
2. INPUT DATA AND PARAMETERS (Describe the list of data and parameters required to perform the function)
- Total bandwidth (default 20 Mhz)
- Sampling frequency (default 30MHz)
- Occupied bandwidth (same if we ignore guard sub-carriers)
- Sub-carrier spacing (default 15kHz)
- Number of sub-carriers in the bandwidth (with guard sub-carriers if we need them)
- Number of sub-carriers per Resource Block (default 12)
- Number of Resource Blocks for a given bandwidth (default 200)
- Number of Ressources Blocks per Ressources Blocks Groups (1 to 4)
- OFDM symbol per slot (default 7)
- Frame duration 10ms, subframe duration 1ms & slot duration 0.5ms
- Number of user equipments
- The scheduling algorithm used (possible combinations if the time allows to implement them)
3. DESCRIPTION OF FORMULA AND ALGORITHM (If your subject involves formulas, explain them in this section. Label and explain the variables used.) (Describe the algorithm used. The description should not be in a computer language but in the form of a pseudo-code: « In programming, the pseudo-code is a way to describe an algorithm without reference to a particular programming language. The writing pseudo-code can often take well to the extent of the difficulty of implementing the algorithm, and develop a structured approach in its construction. (Wikipédia) ». Diagrams can be used too.)
3 algorithms: proportional fair, round robin and max CQI.
4. OUTPUT DATA (Describe the list of output data of the function. What are the results of the simulation?)
- The execution time of the program
- A recap of the parameters
- The size of datas handled
- The size of datas received per client
- The highest and the lowest radio conditions reached by each client
- The list and number of ressources blocks groups allocated to each user
- The theoric & effective throughput reached by the system (to compare the different scheduling algorithms)
- (if the time permit to develop this feature) A recap of the connection/disconnection of clients to the channel
5. VALIDATION ON ONE EXAMPLE (Describe one hand-made example of the algorithm steps. The purpose of this exercise is to verify the accuracy of your work. Take a reduced set of data to describe the inputs, the calculations made, and the outputs obtained.)
6. BIBLIOGRAPHY USED (Describe the list all the references you found to your project: title, author, year of publication, website, etc.)
Bibliography
Tutorial about LTE - http://www.radio-electronics.com/info/cellulartelecomms/lte-long-term-evolution/3g-lte-basics.php
French wikipedia article on OFDM - http://fr.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing
French blog article about 4G and OFDM - http://4glte.over-blog.com/article-ofdma-103962236.html
OFDM tutorial - http://www.radio-electronics.com/info/rf-technology-design/ofdm/ofdm-basics-tutorial.php
French course talking about OFDM - http://www.supelec.fr/d2ri/flexibleradio/cours/cours-ofdm-french.pdf
Article about fading and multipath - http://www.mike-willis.com/Tutorial/PF15.htm
Frame structure and more - http://3gpplte-longtermevolution.blogspot.fr/2010/06/introduction-to-lte.html
LTE: the evolution of mobile broadband - http://www.comsoc.org/files/Publications/Tech%20Focus/pdf/2010/jan-sample/6.pdf
An Investigation of Dynamic Sub-carrier Allocation in OFDMA Systems - https://rose.bris.ac.uk/bitstream/handle/1983/325/Peng_IEEE_VTC_Spring2005.pdf?sequence=1
Subcarrier Allocation In OFDMA With Time Varying Channel And Packet Arrivals - http://www.eee.metu.edu.tr/~elif/Publications/B15_TUY_euroW2009.pdf
Sub-carrier allocation in OFDM systems: complexity, approximability and algorithms - http://ceng.usc.edu/assets/002/64813.pdf
OFDMA basics - http://www.slideshare.net/deepakecrbs/ofdma-basics http://www.editions-eyrolles.com/Livre/9782212129908/
LTE Downlinki scheduling - http://www.nt.tuwien.ac.at/forum/?tx_mmforum_pi1%5Baction%5D=get_attachment&tx_mmforum_pi1%5Bfid%5D=att196
Physical layer parameter - http://www.lteportal.com/Files/MarketSpace/Download/325_5-23commsdesign.pdf
LTE et les réseaux 4G, Editions Eyrolles - http://www.editions-eyrolles.com/Livre/9782212129908/