Throughput Optimization in High Speed Downlink Packet Access (HSDPA)(2011)

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      In this paper, we investigate single user throughput optimization in High Speed Downlink Packet Access (HSDPA). Specifically, we propose offline and online optimization algorithms which adjust the Channel Quality Indicator (CQI) used by the network for scheduling of data transmission. In the offline algorithm, a given target block error rate (BLER) is achieved by adjusting CQI based on ACK/NAK history. By sweeping through different target BLERs, we can find the throughput optimal BLER offline. This algorithm could be used not only to optimize throughput but also to enable fair resource allocation among multiple users in HSDPA. In the online algorithm, the CQI offset is adapted using an estimated short term throughput gradient without the need for a target BLER. An adaptive step size mechanism is proposed to track temporal variation of the environment. Convergence behavior of both algorithms is analyzed. The part of the analysis that deals with constant step size gradient algorithm may be applied to other stochastic optimization techniques. The convergence analysis is confirmed by our simulations. Simulation results also yield valuable insights on the value of optimal BLER target. Both offline and online algorithms are shown to yield up to 25% of throughput improvement over the conventional approach of targeting 10% BLER.


      CQI reports are intended to accurately reflect the HS-PDSCH performance that the UE can support in the existing wireless channel conditions. It is recommended in that, in static channel conditions, the UE report CQI such that it achieves a block error rate (BLER) close to 10% when scheduled data corresponding to the median reported CQI. In practice, the accuracy of CQI reports in reflecting HS-PDSCH performance is influenced by the wireless channel conditions.


1.  The code and power allocation across users.

2.  To maximizing the link throughput for each user for a given resource allocation.

3.  Higher round trip delay.


       An adaptive algorithm to achieve a given target BLER using the stochastic gradient descent method, which adjusts the CQI offset adaptively based on the short term BLER obtained from the ACK/NACK history. By searching through different target BLERs, we can find the throughput optimal BLER offline. The proposed algorithm can be implemented at the UE as well as at the Node B. When applied at the Node B, in addition to achieving the target BLER, it can also save transmit power. This algorithm could be used not only to refine CQI-BLER alignment but also to enable fair resource allocation among mobile users in HSDPA. Standard stochastic approximation (SA) algorithms typically require a decreasing stepsize.


  •  Higher peak Downlink Data rates.
  •  Reduce Round trip Delay.
  •  Higher Data rates up to 84 MB/s.


  1. Server Module.
  2. Path Set Module.
  3. Packet Transaction Module.
  4. Client Module.

Server Module:

    Server module is used to upload the file to the user and view to the user file request. If the server to accept the user file request the control is passing to the router otherwise the server to reject the user request, automatically the request is deleted and user download option is canceled.

Path Set Module:

    The Path set module is used to set the path to transact the files based on this path selection. The server to provide the ten possibilities based on the shortest path. Normally, twelve towers are used for this transaction process. For each transaction, the transaction path takes minimum four towers or five towers.

Packet Transaction Module:

   A Packet transaction module is used to split the file into eight packets in same size and then the router send the packets server to client, the client returns the acknowledgement to the server. The server once gets the acknowledgement; send another packet to the client. If tower size is less than the packet size, the server can’t send via the tower.

Client Module:

      The Client module can view the server uploaded files and send the download request to the server. For downloading files the client registers their personal details. After login, the client can change their password and download the server accepted files.

Hardware Requirements:

•         System                        :   Pentium IV 2.4 GHz.

•         Hard Disk       :   40 GB.

•         Floppy Drive   :   1.44 Mb.

•         Monitor           :   14’ Colour Monitor.

•         Mouse             :   Optical Mouse.

•         Ram                 :   512 Mb.

•         Keyboard        :   101 Keyboard.

Software Requirements:

•         Operating system        :   Windows XP.

•         Coding Language       :   ASP.Net with C#

•         Data Base                    :   SQL Server 2005.

Click here to download Throughput Optimization in High Speed Downlink Packet Access (HSDPA)(2011) source code