Energy-Aware Resource Allocation Strategies for LTE Uplink with Synchronous HARQ Constraints

ENERGY-AWARE RESOURCE ALLOCATION STRATEGIES FOR LTE UPLINK WITH SYNCHRONOUS HARQ CONSTRAINTS

ABSTRACT:

In this paper we propose a framework for energy efficient resource allocation in multiuser localized SC-FDMA with synchronous HARQ constraints. Resource allocation is formulated as a two-stage problem where resources are allocated in both time and frequency. The impact of retransmissions on the time-frequency problem segmentation is handled through the use of a novel block scheduling interval specifically designed for synchronous HARQ to ensure uplink users do not experience ARQ blocking. Using this framework, we formulate the optimal margin adaptive allocation problem, and based on its structure, we propose two sub-optimal approaches to minimize average power allocation required for resource allocation while attempting to reduce complexity. Results are presented for computational complexity and average power allocation relative system complexity and data rate, and comparisons are made between the proposed optimal and suboptimal approaches.

EXISTING SYSTEM:

 General radio resource allocation problems, particularly for systems such as orthogonal frequency division multiplexing (OFDM) fall in to two major classifications, namely the rate and margin adaption (RA and MA) problems. RA problems try to allocate resources to maximize system throughput for a given power constraint, while MA problems try to minimize transmission power and maintain a minimum throughput guarantee. The latter of which is essential for energy efficient scheduling. In recent years, MA problems have been well-studied for a general OFDMA transmission system. However, more modern systems, such as 3GPP-LTE, utilize localized Single Carrier Frequency Division Multiple Access (SC-FDMA) at the physical layer for uplink transmissions. With localized SC-FDMA, subcarriers can only be allocated contiguously in frequency. The use of localized SC-FDMA has been shown to offer improved peak to average power ratio (PAPR) compared to OFDM. This however imposes a limitation of contiguous frequency block assignment, and thus eliminates direct application of traditional MA framework as described above. Furthermore, the finite set of modulation and coding schemes (MCS) used in modern communication systems dramatically increases the optimal allocation complexity.

DISADVANTAGES OF EXISTING SYSTEM:

·       The objective function in this case is to maximize the cell transmission rate rather than minimize transmission power.

·        Mobile battery resources are not efficiently utilized.

PROPOSED SYSTEM:

We propose a method of performing resource allocation that exploits the periodicity of the HARQ process in scheduler design. We propose the use of a block time-frequency domain packet scheduler (BTFDPS). This approach reduces the amount of scheduling decisions required for uplink traffic in addition to simplifying incorporation of synchronous HARQ into the framework. At each block time-frequency frame, resources are allocated dynamically relative to the required throughput, priority, and number of on-going transmissions. Power allocation is minimized per unit time to meet constraints resulting in minimizing energy expended for transmission.

ADVANTAGES OF PROPOSED SYSTEM:

·       Power allocation is minimized.

·       It reduces the amount of scheduling decisions required for uplink traffic.

SYSTEM ARCHITECTURE:

SYSTEM CONFIGURATION:-

HARDWARE REQUIREMENTS:-

ü Processor                  -        Pentium –IV

ü Speed                        -        1.1 Ghz

ü RAM                         -        512 MB(min)

ü Hard Disk                 -        40 GB

ü Key Board                -        Standard Windows Keyboard

ü Mouse                       -        Two or Three Button Mouse

ü Monitor                     -        LCD/LED

SOFTWARE REQUIREMENTS:

•         Operating system :         Windows XP

•         Coding Language :         Java

•         Data Base             :         MySQL

•         Tool                     :         Net Beans IDE

REFERENCE:

Dan J. Dechene and Abdallah Shami,  “Energy-Aware Resource Allocation Strategies for LTE Uplink with Synchronous HARQ Constraints”IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 13, NO. 2, FEBRUARY 2014.